This is perhaps the most frustrating thing I have ever experienced. My friend and I always used to transfer files over AIM in Windows. His computer finally crashed and he decided to get a Mac. So he's now using an iMac purchased two months ago running Leopard. He loves it. The only thing he doesn't like is that we can't really transfer files. Just to let you know what we've tried on his Mac: iChat, AIM, Adium, and MSN Messenger. He has Verizon FIOS with 50Mb download and 10Mb upload. I have similarly pretty fast connection at home and at school as well. -MSN Messenger doesn't work well because the transfer speeds are slower than dial up speed. -AIM isn't supported anymore on the Mac. Doesn't even run in Leopard. -Adium won't even allow him to send me files. It sucks because he liked Adium the best of all IM clients. -iChat works on and off. It's weird but it'll transfer files then stop somewhere along the way. He'll then have to resume the file transfer by resending the file. It becomes very annoying because we may have to do it 10-15 times in one transfer. We don't know why this happens. We don't know of any other solutions. He's behind a router (Actiontec mi424w router) but that's for his internet connection to FIOS. I don't have anything stopping me at my end because I can transfer files to my other friends perfectly. So we don't know what to do anymore. His computer has all the latest updates for Leopard. This is pretty frustrating and I don't know what else to try or to configure anymore at this point. I've even done remote desktop to his Mac to check his firewall settings but there's nothing even listed that would block file transfers. Any help we could get is appreciated.