yes, it is possible to run asp.net on apache. You just need to use Apache with mod_aspdotnet module installed. Refer http://httpd.apache.org/modules/#mod_aspdotnet
I second mono. Only had the chance to use it for C#, but it's very, very nice. The following docs might be able to help as well. http://mono-project.com/Mod_mono http://mono-project.com/Guide:_Porting_ASP.NET_Applications