For all you ASP.NET developers our there, Http Compression is one of the most important things to consider adding to your application.
It can speed up download times by about 5 times, saves on bandwidth, and improves on SSL performance.
There are lots of vendors out there, pipeboost.com, xcache, and many more.
But I wanted to make sure everyone has heard of the open source c# ziplib version:
http://www.blowery.org/code/HttpCompressionModule.html
Works great unless your doing Server.Transfer, due to a MS bug, which has been fixed in a hot fix and can be obtained.
http://support.microsoft.com/default.aspx?kbid=821156
At www.pipeboost.com they have a link on their home page you can use to see a before and after difference, and it will tell you if your page is compressed and working. Pretty cool tool. Check it out
Speed up your site!