Yes, it's very possible It's just like previous CFW's however only 3.80 themes will work (previous or future firmware themes do not work). Here's a slightly out-dated guide but it should do the trick - http://forums.exophase.com/showthread.php?t=2226
Also here's a video tutorial on Youtube - http://uk.youtube.com/watch?v=CuZosDivnjQ&watch_response
And a list of some 3.80 Themes [here]