You can check out the Tekkit wikia for recipies and information on what the machines do, or check out Eloraam's website for the official unofficial recipe list.
Wiki: http://thetekkit.wikia.com/wiki/Category:RedPower2
Eloraam's Site: http://www.eloraam.com/
The official unofficial recipe list (is updated for PR5e but most recipes still apply): http://nemesis.evalq.net/RedPower2/recipes.html
There are a ton of things you can do with RedPower, but first you should check out the wires (Cook 1 copper or 1 iron and 4 redstone in the Red Alloy Furnace to get 1 Red Alloy Ingot, then three ingots top to bottom to get 12 wires). You can use these wires just like redstone, except they can travel up and down walls, can be "disrupted" by strips so they don't affect other wires, and other things. Have fun
Edit:
And if you're looking for specific examples of cool things, I like setting up my front door system with a semi-locked pressure plate, using a XOR gate connected to two levers and an and gate connecting the xor gate and the pressure plates to the door. The XOR gate states that the output is on when the inputs do not match (0/0 = 0, 0/1 = 1, 1/1 = 0). Not the most advanced system in the world, but serves nicely as a player only pressure plate (until mobs can flip levers that is).