yes, you can. you can use virtualPC which is free or the better, VMWare. both will let you connect your virtual OSes to the internet. on a x64 host OS, you can setup both x86 and x64 guest OSes.
there are tonnes of resources on how to set these up.
for virtual pc check this
http://www.windowsnetworking.com/art...-PC-Part2.html
i am assuming that you will use virtualPC as vmware is pretty expensive, but lemme know if you need any documentation for vmware.
also, setting up networking in virtualPC is not so simple, you will have to install a MS LoopBack Adapter on the host OS (just a virtual adapter) and then enable internet connection sharing for it.
hope this helps