How do they create those cute rainbowed text signatures in this forum? Those are cute!

Go to user cp > profile > in the edit signature box just add what you want, check out the VBcode (http://www.lissaexplains.com/forum//misc.php?s=&action=bbcode) code page and look at the "Using Different Colors, Sizes and Fonts" section for the codes you need to use to change colours etc.