ASP.NET + Apache
first check out IIS6 (see why IIS6 is a better choice to run ASP.NET than apache here and here)
Run ASP.NET on Apache:
XSP
mod_mono
mod_aspdotnet
Cassini (Cassini on Apache)
CassiniEx (enhanced)
see also http://dotnetjunkies.com/WebLog/kris/archive/2004/06/25/17578.aspx on running apache + asp.net