Graham  
[b]bold text[/b]
[i]italic text[/i]
[u]underlined text[/u]
[br]=line break
in the following n=number h=hex digit
[size=nn](size in pixels) text size[/size]
[color=hhhhhh]coloured text[/color]
The next one also works without BB tags
[url]http://xtips.mobi[/url]
[url=http://xtips.mobi]text link[/url]
Use a smiley code as the text and you get a smiley link
[img]http://xtips.mobi/xbut.png[/img]=
[url=http://xtips.mobi][img]http://xtips.mobi/xbut.png[/img][/url]=
[email]you@nomail.com[/email]
(c)=© (r)=® (tm)=™
Other html entities can be used in the format &#number;
Most BB codes can be nested
20PX GREEN BOLD ITALIC UNDERLINED
[code].....[/code]