how do I Mod my cell phone (software)

:D hey, just want to know if any of you lot know any programs that can MOD my Mobile phone (software) btw I own the SE-K800iIve seen some cell phones modded on these links -http://www.youtube.com/watch?v=Eqb_UxrOSRQ
http://www.youtube.com/watch?v=hRdVY-N_2xQ&feature=relatedplz fill me in with some info ;) thanks in advance!

that first one is just a theme combined with the software from a sony ericsson walkman phone - there are websites that sell these updates (though i reckon you can manualy do that from the sony ericsson website)in fact when i bought my sony ericsson w220 (laugh and i will kill you) i found a theme creator from the sony ericsson website, which i thought was cooloff topic, does your k800 suffer any slow-down? my one on vodafone (but restored the original firmware) does

It hasn't suffered any slow-down, untill I got tonz of java games for it ! Now it takes a few minutes for it too start up and load every thing lol. Did you see the PSP mod, I was wondering how I can acheve that?.w220 = ;D lol, kill me ;D

OK if you want to mod your phone i suggest going to Sony erricson mod sites such as SE-NSE, Top Sony(Google these) and Read the tutorials there before atempting to do anything.