In addition to software recommended above, acquaintances of mine recommend igal
) or album
igal and album do not require anything special from the web server, but they require that you have access to a computer running Unix (which means that MacOS X should work), or Cygwin
) or ActiveState Perl for Windows
IDS requires CGI and Perl on the web server, so it could potentially be a security risk. Similar problems are well known to crop up for PHP software such as Gallery or Coppermine, using these means you'll have to upgrade frequently
I mention "security risk" because I'm in the web hosting business, and one of the most tedious tasks I have, is to clean up after the mess of people using software with security holes.
What I use? Semi-handcrafted HTML combined with use of the "convert" program in ImageMagick