[SOLVED] System file patcher. Time to make a theme

Well its about time to make a start on my own theme. I understand I need to patch three files so I can use it.
So which, in your experience is the best "file patcher" utility.
Which software program should I use to help build the theme, bearing in mind I do not want to be locked into having a 3rd party app. always installed to be able to use my theme (I'm thinking style builder here). I used to use ResEdit when on XP, along with the "standards" so I'm looking for something along the same lines.
Tutorial pointers also gratefully received!!
TIA

Here ya go. It even works well with the SP1.