iPhone, iPad & iPod touch

ok download the following
icon maker
photoshop
paint.NET (alt for photoshop)

so when you get those three i recommend using icofx to make the outline of a app cause it was made to create apps
anyways so you get the outline save several of them
if you are inexperienced at photoshop or paint.NET then i advise you to maybe watchsome tutorial jsut so you get some basics
anyways once you have around like 20 icons save it into a folder named icons
then maybe you want a wallpaper find a picture 320 x 480
and call it wallpaper or lockbackground your choice and easy as that
put the 2 things into another folder called my theme
and ssh that into themes
/private/var/stash/themes

this is just the basics you can go beyond but you gotta know what your doing and the people that know what they are doing dont
even know how to explain like me im not that good but i made a theme using other templates of other peoples LOL but yeah whatever
so maybe make a exotic theme or maybe just a playful theme now you can control that

im going to try that

Using bundle identifiers is how you do it now. i.e. com.apple.springboard