In any possible script there are some somall tuts to make this.
In order to make a skin it's better to first start modding the default one .. to learn how to change some images, the css code and then a header or a footer. Start with smaller things and improve each day.
Afterwards you'll get to the point you'll design a skin in Photoshop, slice, code the HTML tags and the copy-paste them into the appropriate place in the forum code. Sounds tough, but it's not
