Software to emulate Windows 7 on OS X, for developing I need to load Windows 7 under OS X. These are my Macbook Pro's features:


Mac OSX 10.7.2
2.3 GHz Intel Core i5 
4 GB 1333 MHz DDR3


Which software would be the most suitable for me, considering that I want to focus on developing .Net Applications.

I know there's VMWare Fusion and Parallels but maybe there's something better or if not, which one would be the best for me? Thanks.
I'm a Fusion user and have been for a few years now. Fusion 4.x has been a nice upgrade and it's a very stable way to run the latest Windows OSes on OS X. I think you'll be fine with Fusion or Parallels -- both are tested and support Win7. VirtualBox is a nice option, but be prepared to go it alone if you run in to any issues.

None is really better than the other in my opinion. They all have some overlapping features and they all have some features that are unique to the product. Try before you buy if you can.

I will comment on your system: you're going to find things running slow with only 4GB of RAM and a Win7 VM for development work. Visual Studio is a pig and it's running on top of an OS that's not terribly great at memory management. I'd recommend you upgrade that 4GB to 8GB (or more if your model supports it) if you want the best virtualized OS experience.