I use Visual Web Developer and at present there is no option to delete those projects from the Menu. I believe it is the same with Academic Edition. What you can do though is go to Websites directory and delete the project you don't want in the list, or if you don't want to delete it, just try moving it to some place else. Then when you click that project again in the list, it will give a message saying it cannot find the project, do you want to remove it. Click yes.
If you have default installation, I believe the directory path is this:
C:\Documents and Settings\UserName\My Documents\Visual Studio 2005\WebSites
Also, if your projects are not in default directory but some place else and the list refers to that location, just remove the project from that location.
[bullpit^-^]