simple text replace

[Vaelen]

OK, request should be fairly simple. I've also searched around and not quite found something that does -exactly- what I need.

Basically, I want it to so when someone types a certain word, say "bob" for example, it tacks some VB code onto the word. Basically a word replacement, but when I tried a replacement script, and when I had "bob" replace "{code}bob{/code}" it was just a loop because it picked up the word bob again... is there anyway to make a code ignore that somehow?
All I really want to do is tack on colored, bold parentheses on the edges of a few words.

Any simple way to do this?

Well, I got my other code -sorta- working, but I have to put periods in the "replacement" words just so theres not an endless loop of the replacement. I also tried using the auto geek linker and the other auto link scripts, but they won't work for some reason ;\