SpaceSimCentral

Definitely try to find a game engine so you don't have to reinvent the wheel on a lot of stuff. Also make sure to have a complete design doc before you code...it will save a lot of headaches.

Go with the XNA development kit. It's free, it's easy to use, it's got a great set of tutorials, and so on.I've been working on my game for over a year. It takes a lot of hard work. Google XNA, get started with it, and ask a ton of questions.

Personally, the game I'm most looking forward to is StarDrive! I've been working on it for over a year at this point. If you're looking for Master of Orion IV or the next Escape Velocity, I hope to be scratching that itch for you shortly.