For those of you with some interest in X-Wing Alliance, go check out www.xwaupgrade.com . The graphical upgrade is AMAZING!
There's also the TIE Fighter Total Conversion, http://www.tftc.gaylenol.com/ , which imported all of the missions and sound files and stuff from TIE Fighter, so you get TF in the XWA engine. Of course, if you go the other way, it's possible to import the XWAUP models into TIE Fighter, but that's not quite as easy.
Just thought I'd mention this here, let me know if any questions.