one time I saw a guy using iPhone to view Google map and Youtube without wifi; that happens After jailbreaking of my iPhoneOh, my god, I am a freak about what happen his iPhone. he told me what he have done; actually it is quite easy; now this guide will show you how to do this;
this guide have two parts:
1)How to view Google map without wifi;
2)How to view YouTube videos without wifi;

Part 1.How to view Google map without wifi
In PC: First, show you two maps (Washington)in my iPhone:


Cool, I drive about the city without GPS, without connecting with Internet just view up my iPhone;
Ok, let?s start:
1. download this opensource free app Global Map Download Tool (GMDL) in your computer:
  http://www.in7ane.com/psp/gmdl0.5.05b.zip
(it does require Microsoft .net 2 from http://www.microsoft.com/downloads/ )
lots of people know cygwin, in7ane, but had difficulties with how to use; So I find this app. it is developed by person and will be shared with anyone;

It seems slightly complicated, but ok, you will get familiar with it after several steps;
(tips: newest edition can support Yahoo maps, Live Search Maps)
2. decompress file in your system and go into its folder > ?bin? folder > ?DeBug? folder > click ?Global Map Download Tool.exe? to launch the program.
3. in select ?map source tag? you can choose ?satellite? or ?Google map? as default output image; default image output simple traffic map like first image above;
4. specify location you want and click ?download the map?, a pop-up asks you where to save your maps, you must choose a empty folder or create new one;
5. then you can see a preview window, the image is divided into several small square images and you can choose which one is not outputted; Ok, now choose ?Uncheck any tiles which…..? button. wait seconds, program would remind you when finish:

6. after program creative GPSFS files, click “->iphone” button;
then a pop-up requires you to choose output folder, you can choose a empty one or create a new one;
click ?process?, OK;

In iPhone:
(require: jailbreak your iPhone)
1. download this free application;
http://www.in7ane.com/iphone/old/iLM-0.2.1.zip
decompress iLM-0.2.1.zip, upload iLM.app to applications directory;
set 755 as the property of directory
2. move GPSFS file in folder you have saved Google maps files to var/root/media/maps in iPhone;
Ok, now you can view your Google map or Yahoo map without wifi;
just run iLM when you need to view Google maps;

Part 2.How to view YouTube videos without wifi;
this part is not so complicated, what you have to do is to download Youtube video and upload to your iPhone;
I know there are many online download websites can do that, but I do not recommend using online download websites;
You know many of them require your email address, that is not the problem but I assume that you spend half an hour to download video, another half an hour let website sends video to your email, finally spend half an hour download video from email box to local system.
Oh, my god, spend one and half an hour just to download a 10 minute video.
Besides, sometime lag your computer or give you mess error pop up;
So, my advice is to use program;

two kind of software:
1.plus-ins: like downlaodhelper for firefox or realplayer 11
advantage: free
limitation: just support some websites and not support batch download;
Complicated operation for newbie and frequently pop error message;
2. Specific YouTube downloader;
like this program: YouTube downloader
advantage: batch download, some of them have conversion or out advanced function, fast and stable;
limitation: charge for usage, but some trial edition have not function limited;

Anyway, this part I introduce how to download youtube into iPhone with program;
1. download the program: YouTube downloader:
http://www.flash-on-tv.com/youtube-downloader.html
Install in your system and open up the program
2. open YouTube and choose page you like:

3. Run the program, turn on recorder function for automatically detect and download videos off YouTube:

you needn?t copy and paste URL, I like this function;
After downlaod, just batch convert them into mp4;
select all files > click convert icon above > choose mp4 for iphone in output box > OK;
4. Open iTunes, drag your videos into library or choose Add File to Library > Add Folder to Library
5. sync iPhone,
Ok, all done;

my iPhone is 16G, spend 2G to store about 70 YouTube videos; that is great;
view YouTube without wifi when I come back my town;

OK, feel free to try above methods in your iPhone by yourself.

Why not just use the maps and youtube app built into the iphone?

Yes, iphone have own buildt-in Youtube and maps apps, but them have to work with wifi. You know, when away from wifi service area; Your phone would be just a media player but not a web device;

here I should claim why I want to write this article and what you can get from this article;
though wi-fi have been used for years, but not all area are covered; i.e. airdrome or countryside. when you wait in airdrome or drive in countryside road with nothing interesting to consume time that would be bored as hell; unfortunately, without wi-fi your iphone can?t get in Youtube or use safari. it means that it just a common phone like other cellphone; is there ways to normally use iphone and exert her function when wi-fi is not available?? my answer is yes, even without wi-fi, you iphone can still view google maps as GPS, besides, you can also view Youtube video to consume time; all you have to do is follow this guide and install some apps;
notes:
1. make sure jailbreak your iphone first, more information in this site:
http://www.modmyifone.com/wiki/index.php/Jailbreak_iPhone
2. you are using Microsoft windows system (vista,xp,2000)in your PC;