One of the more demanded Jabber features for the last years has been file transfer. The set of required JEPs has taken a lot of time to be written, a lot of discussions and a lot of hard work from their writers and contributors, but they were finally approved by the Jabber Software Foundation Council around October 2003.
Tkabber first introduced file transfer support in july 2002, but on that time the JEPs were not approved by the JSF and it was hard to make a transference between different clients.
Now file transfer is a reality in Jabber, with some of the most important clients fully supporting it and more clients to come. Right now it's possible to do file transfers between Tkabber, Psi and Exodus at least. Hey, it's even possible to transfer 700 megs files!.