No, the operating system used by the iPod touch and iPhone, which is a variation of Mac OS X, is very secure and will not get viruses. This is mainly because an iPod touch/iPhone cannot download files from the Internet, which is where the vast majority of viruses come from.
If I download some cracked apps, is there any way i can verify them without jail breaking my iPhone? When I try to sync them they say "app cannot be verified" or something like that. Thanks 
no u cant
I’m being screwed by AT&T and their rate plans for the iphone 3g. Is there an effective way to unlock my phone so that it can work with another carrier like T-Mobile? I heard of this company called YESSIM that makes sim cards that can unlock the iPhone 3G. Any thoughts on this? Your input is highly appreciated.
of couse you can unlock the iPhone 3G
please visit the Dev-Team site : http://blog.iphone-dev.org/
they are the ones who unlocked and jailbroked the iPhone
1) Download pwnagetool or QuickPwn if your on Mac
2) Download WinPwn if your a Windows user.
Procedure is listed in the above site and also lot of other sites as well.
you can do it yourself if you have a pc and internet, no need to pay any third pary guy some 10 or 15 bucks.
try google with : Gizmodo , for more procedures / articles.
hope this helps.