Qwix is a very simple to use XBox Remote File Management and ISO Creation Tool.
Have a bunch of ISO's sitting on your PC that you need to load onto your XBOX? Open up Qwix and use the ISO batch upload tool.
You select a game from your XBOX that you want to create an ISO from, and tell it where to save on your PC. You can even choose to crosslink files, which means that it will take common areas of the game and "cross" them so that they don't have to appear multiple times. That saves valuable diskspace, and can change a DVDR game into a CDR game!
If you are also using Avalaunch, then you need to go into your avalaunch.xml and make sure that BOOST mode is enabled, because you are gonna love that. When combined with Avalaunch, Qwix has the ability to upload ISO's to your xbox at speeds much faster than you could achieve with a normal FTP client.