While browsing commandlinefu.com (a very useful site, by the way), I found this gem that uses Python to quickly set up a webserver for the current directory in Terminal. First launch Terminal and cd to the directory you'd like to access via your web browser. Then just use this command to start a webserver serving just that folder (and folders within it):
python -m SimpleHTTPServer
The webserver runs on port 8000, so to access the pages in your browser, you'd use http://localhost:8000. If you'd rather run the webserver on another port, just include the port number on the python line: python -m SimpleHTTPServer 8080.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090423060145578