I am tring to put VB code into my forums that I am surrently working on. Do I go
$content = str_replace("[url]","<a>",'$content");
I was just curious of course this is just an example
No, you are going to need some regex to match what is contained inside the [url] tag, and then be able to transfer that to the href attribute of the <a> tag. I would use PCRE.