Here's a link to a list of available BB codes that work with these forums:
http://docs.simplemachines.org/index.php?topic=57
I was actually looking how you display a title for a link (http://docs.simplemachines.org/index.php?topic=5), rather than display the whole URL (as above), so if other people were wondering the same thing, you do it thus:
[url=http://yoursite/]Site Name[/url]
As Opposed to;
[url]http://yoursite/[/url]