How to prevent rust on your tools
Keep them dry, you fool!
The easiest way to prevent rust from forming on your tools is to keep them dry and away from humid air. With that said, there are plenty of ways to get rid of rust if your tools have already rusted. I ran into this problem myself when a broken window caused my tools to rust in a tool shed over the course of a winter. I've learned my lesson: no more windows on the tool shed. I also learned how to clean all the rust off my tools and have them looking as new as the day I bought them (well, almost).
Don't buy any special product just to remove rust
As it so happens, there are some things that you should have at your house that can be used to clean tools. If you don't have these things, go out and buy them, because you'll need them sooner or later for something anyway.
The first thing you need is some fine steel wool. Cover your rusted tool with WD-40 and then rub them down with the steel wool. If you don't have any WD-40, you can also use kerosene, but who has kerosene these days?
If all this doesn't work, you might have to go for a stronger solution. Go to your local hardware store and ask for Naval Jelly. Don't put it on your belly button, because it'll probably cause a rash. Use it as I instructed above with the WD-40.
After you've cleaned the rust off your tools
Now that you've got the rust off, use a clean rag to get all the oil off. Get a product called automotive paste wax and put it on all the exposed metal parts. This will ward off rust during those long months when your tools aren't in use.