Its not really feasible to download a 1GB+ file on the mobile phone, though theoretically it may sound okay, I've read there are lots of issues like disk caching and poor transfer speeds. Besides these apps are poorly coded and the amount of data flowing through them cause very frequent hang ups and crashes.

There is a P2P app for the iPod touch (Which will perform a LOT better than S60 and WinMo for sure!), check it out

[UPDATE] Torrentula.app v1.2 (should work on all firmwares) - iPod touch Fans forum