Wireless Rocket Launcher

Just getting into arduino, and the first project I want to attempt is over my head. I have built the air compressed rocket launcher from Make Magazine. It has a push button connected to 2 9v batteries and a sprinkler valve. The button completes the circuit between the 9v and the sprinkler valve. I want to use arduino to make this wireless. From what I have researched so far it looks like I will need some form of Xbee and a way for an arduino board to receive the push button signal to complete the circuit.

Any thoughts on the setup and code?

Probably cheaper/easier to use a simple rc tx/rx setup.

Can you elaborate more on that? I literally just finished Make: Getting Started With Arduino, that is how green I am. Or, could you point me in the direction of some resources? Thanks so much! :)