Search Engine Safe Urls seem to be a talked about topic these days… mod_rewrite being the de-facto for Apache users… there are a couple out there for IIS:

urlrepl — this is my favorite, mostly because it’s free. You can configure it either from a web browser or an ini file. Downsides: no regular expressions, configuration applies to all virtual servers defined in IIS.

Spider Safe Url — this one is nice.. but in the little testing that I did with it, it killed pages that didn’t have url variables… so while this would work:

/products/detail.cfm/id/23/category/83/

this will not:

/products/detail.cfm

which means that if you have single pages that don’t need url vars, you can’t use it.. Pete, am I wrong? Open source. Free.

IIS Rewrite — looks like the same thing as urlrepl mentioned above, ‘xcept you have to pay for this one… [on second look, this one is really full featured, moreso than urlrepl]. It supports regular expressions, check out the docs. $99 per server.

ISAPI_Rewrite — This one is really nice as well.. $63 per server, $453 per organization.