If you want the server time that's easy, grab some code at
www.dynamicdrive.com If you want the users time then that's a little trickier. Anime-Loo had one working on his Linux server but I could never get the code working on an NT server. Back when I first started my UBB I had gotten one working and it showed the server time and users time side by side. You can probably find it in the 6.0 mod ideas forum by doiing a search.