Now, I've never completed a game. It wasn't my cup of tea but I have tried it atleast, I don't claim to know the in and outs of it but here are my two cents:
You can emulate the mac os with a powerful computer. That's what I did. It worked, but it wasn't flawless. What you want if you really want to develop apps is a REAL mac.
Gamesalad is a program that helps you create games. I don't know if it's free though.
Here's why I won't recommend it:
You would need a
Fully functional app or game
Marketing plan
A license for selling on the app store
The hardware/software
You also need to learn the programming language or pay $$$ for someone to do it for you.
So unless you're sitting on the next angry birds viral thingie I'd look for a different source of revenue.
Now if you genuinely want to learn how to make apps/games then go for it! If it's just for the dosh there are far easier ways to go.
Links
developer.apple.com
stackoverflow.com
developer.apple.com/appstore/guidelines.html
developer.apple.com/xcode/
Good luck
