I suggest reading through some of the stickies:
As far as equipment, you'll love the cooler as a MLT. If you're building it yourself, definitely go w/ a 10g in case you want to upgrade at some point (and you will...trust me).
Your 10g kettle will work fine for 5g batches and the 5g kettle will be nice to have around for heating strike/sparge water.
I'm sure I'm forgetting something, but that should at least get you started. Oh and one last thing...just jump in and do it. I was really intimidated by the process at first, but after getting a batch or two under my belt I realized how simple it really is. You'll probably make a few small mistakes but in the end you'll still have made beer.