I have Snow Leopard 10.6.4. Can I install XCode 4 in that machine? If not, what is the minimum version of Mac required to install XCode 4?
Officially, it says on their website that the minimum is 10.6.6. However, I have seen XCode work fine on unsupported versions of OSX in the past. Heck I have seen people use XCode on PowerPC based Macs.
The thing is that you should be able to update your version of Snow Leopard using standard Mac updates to the latest version. If you need some help getting the updates on the system let me know.