Compounding this problem is the bi-metal interaction between aluminum wires and the copper/zinc connectors found in most recepticles and switches. The aluminum oxidizes more readily and the problem becomes worse. There is an answer, however. Aluminum recepticles and switches are available which eliminate the bi-metal interaction and will give a good connection, eliminating overheating. I think that they are slightly more expensive than the standard recepticles, but they are a must.
If the recepticles in the house are all aluminum you are likely fine. If not, they can easily be replaced by yourself or an electrician if you aren't comfortable doing the work. As with any electrical connection, copper or aluminum, you must ensure that the connections are made tight to avoid higher resistances. One other thing to watch out for is any additional wiring that was done to the house. If it's all original aluminum you should be fine, but if copper wiring was spliced, twisted, or connected to the aluminum it has to be replaced. If you have any concerns I would consult an electrician, and maybe have them do an inspection on the house.
Aluminum wiring, like knob and tube wiring, is often viewed as unsafe, but it's usually not the original wiring that is a problem, but what's been done to it. I just bought a house with K&T and the original wiring is fine (albiet with no ground), but the light fixtures aren't wired properly. I'm replacing it myself right now, which requires a lot of patience and usually a helper. My 2 story house would have cost well over $10,000 to get rewired including the basement and attic, so it's well worth it.
Hope this helps.