What software should I use to mine alt coins?
You will need to download some mining software, cgminer was what I used to use, there are others out there to. But find yourself a pool that has the altcoins u want to mine, most pools work on pointing your port at a different values for the different coins. Most good pools have guides for setting up the different miners software for their pool.  Coinotron was always one of my favourite pools and it is still going :) hope this helps