@Hits
I just debranded my Fido (Rogers) Z710 successfully a couple of weeks ago. I was pretty overwhelmed too, there is a lot of information. I mostly wanted to be able to use MP3's as ringtones.
First read this article: http://www.topsony.com/forum/showthread.php?t=28
I used XS++, the newest version is XS++ 1.6.7 download here: http://forums.se-nse.net/index.php?showtopic=13690
I found this article helpful: http://www.topsony.com/forum/showthread.php?t=3519
note that you can now use "BreakXS" on DB2020 phones as of XS++ 1.6
If you have any more questions feel free to ask.
harto