Just a quick warning, stay the fuck away from FontSwap.
I tried it yesterday, seemed to be working like a dream. Then i clicked on one of the last fonts (it comes with the pack). After respringing, no apps would open and the clock was messed up. Clearly it was lacking in crucial letters and that was making them all crash. Anway after restarting, my ipod wouldnt even turn on. Luckily i realised that the USB mode still worked. So i got Disk aid, found where the font was (Helvetica.ttf) and replaced that bitch.
Apparently, its not developed by Skylark (IPTF forum). Its just another kid whos used the same name. The technique is totally unsafe, because its injecting a new font into the helvtica font file. So if any thing goes to shit, your going to have a hard time trying to reverse the effects.