I built a few basic birdhouses like this:
http://www.cornerhardware.com/index.php?main_page=howto&f=ht071
Couple of things: I mount mine to a pole or small shelf bracket on my porch post so I have a fixed bottom and the front is held on with two drywall screws letting me clean out for the next tenant. I have basically had Wrens living there and hatching babies, which is a delight to hear when mom and dad take turns coming back with a gnat. Also, do not put a little perch on your house. The birds don’t need it and it’s only a handhold for predators. A birdhouse is one of the best projects because if your joints aren’t tight or a measurement is off the bird just doesn’t care. Plus you can use up your scraps and use any kind of saw to make one.
Cornell Cooperative Extension is a wealth of info in birds and birdwatching.
http://www.birds.cornell.edu/nestinginfo/nestboxref/construct
