I think it sounds like a great idea to get him a friend! As far as introducing them, try at first just putting them in the house together. You won't want to put them in each other's faces, or anything...let your first friend come out on his own to meet the new one. In the time it takes him to come out, your new friend might have a chance to investigate the space a little.
Now, before you bring your new friend home, be sure to have a second litterbox (keep it away from your current feline to be sure your new friend won't reject it because it already contains the scent of a different cat) and a separate supply of food and water set up in the bathroom just in case. That way, when they meet, if you find they aren't getting along (if you see them starting to fight, or some such), put your new guy in the bathroom, where they'll get the chance to sniff each other under the door.
After a couple days (could be as much as a week, though), you'll notice them playing together under the door, and very eager to meet one another. At that point, guardingly let out your new friend to meet your current one, and watch them pretty closely for a couple hours, being sure to encourage your current friend and letting him know you are thinking about him and love him.
I hope this helps!! Be sure to spend plenty time with your new friend before you bring him or her home, to be sure they are personable and friendly. There's nothing worse then bringing home a cat you haven't gotten a chance to know, and finding they're not all that friendly.