There is a version available but it's still in development. You need to install an X server to run it.
Fortunately, there are a couple available. Apple's is very good, since it supports hardware accelerated video, integrates nicely with the Quartz (native) window server and is a very easy install. (It only does rootless mode, though.)
I've used both and they're quite promising. I also use Appleworks, which is fine for most Word and Excel documents. If you need to deal with Powerpoints, though, try out OpenOffice.org.
As for browsers, you may want to try Safari when the 1.0 release comes out. It's very snappy and word is that they've added tabbed browsing in recent builds.
While you're at it, you may wish to upgrade to 10.2.4. There's also a sendmail security fix that came out on 3/3.