A buddy of mine has this router and the OS is
OpenWrt White Russian - With X-Wrt Extensions 0.9
Linux 2.4.30 #1 Wed May 9 14:48:55 CDT 2007
anyone got a newer kernel in this one?
or some other OS totally?
WRT54GL, what OS?
What's wrong with OpenWrt? I run it on all of my WRT54G and WRT54GS models and love it. You won't find a 2.6 kernel running on any of them if that is what you are looking for. At least I don't know of any running 2.6 I think because it's too big. 2.4.30 should have everything you need though and it is the most recent of the 2.4 series. I have web servers and php running on a couple of them. This site is running on one of my WRTs:
http://voidmain.is-a-geek.net:81/
http://voidmain.is-a-geek.net:81/