My bet is that the silver can with the R433 is a SAW oscillator and you are looking at 433.something MHz parts. This is a very common config.
They will be set up for on-off-keying, most likely -- also very common.
I do recommend using the Arduino VirtualWire library with these sorts of things:http://www.open.com.au/mikem/arduino/VirtualWire.pdf
This writeup also has lots of good info about the ins and outs of these radios. The virtual wire protocol has some error checking and redundancy in it that you will likely need in any but the very simplest circumstances.
There is a trade-off between signalling rate and reliability/range. Faster is obviously more likely to be affected by noise. But you have to have a certain floor on the rate, as the receiver uses a automatic-gain-control circuit, and too-slow signalling will cause problems with the AGC locking on. Something like 1,000 baud would be a good bet to start with.