I love Strife's Greasemonkey script. I wouldn't even notice if they switched on BBCode again... 
https://addons.mozilla.org/de/firefox/addon/748
http://userscripts.org/scripts/show/9651

https://addons.mozilla.org/de/firefox/addon/748
http://userscripts.org/scripts/show/9651
You would notice php and code tag style would be different. I tried to emulate it when I wrote the script but I didn't have any samples to compare it to so it isn't identical. I didn't even try to do php highlighting (it's even not like php can be used in SL anyway). Some out of order tags would start working (I examined that problem but decided it would require too much work to get close to perfection).