Me and some of my friends are gonna create some retro style games and are wondering if there is a program on the internet that makes songs with beeps and bloops in it and can make a song like the Mario theme song.

Sure, you can use pretty much any MIDI sequencer for that, since virtually all MIDI synthesizers have provisions for simple sine/triangle/sawtooth/square waves. More info here.

thanks

Or if you have a VSTi capable sequencer try:

Quantum64 (emulates a C64 SID chip): http://www.funkelectric.com/~cockaigne/ (the link on the page doesn't work correctly though, so try this: http://www.funkelectric.com/~cockaigne/files/quantum64_v11.zip )

And Monomate (good for retro style basslines), Peach (NES synth), Toad (NES drums) and Triforce (antother NES synth, more programmable than the other two, but harder to use) all available here: http://www.tweakbench.com/