I believe if you have a 100 amp service, that's what the wire is sized for. Now, since you have 200 amp pannel your wire cannot handle the possible load of 200 amps. "ELECTRIC BILL" WILL PROBABLY RESPOND SOON....He knows alot about this subject....

Hollywood

How can I tell what the service is to my home? The meter has a "Class 200" designation on it - is this an indication of 200A service?

Jeff

jduchock, another way to say it is:
Your panel is capable of handling at least 200 amps, and therefore you could connect enough devices in your home to try to draw that much power.
But the service from the power company is not sufficient (wires too small) to safely provide that much power.

Hollywood and rpxlpx are both right. Someone probably upgraded to the 200 amp panel without getting a permit. The most important thing is if the wire size brought to the house is appropriate for the panel. It is possible that the wire is of appropriate size 1/0 if it is copper and 2/0 if it is aluminum. If the wire size is smaller then the service is not likely rated for 200 amps. What you should do is look to see if the panel has an inspection sticker on it from your local code enforcer. If not Find an electrician to look at it and ask him to pull a permit to get it inspected if it meets code. Also, the house inspector you are dealing with probably works for the buyer and they will look for anything to negotiate a lower price, He/or she may really not Know what they are looking for. In some states there is no license to become a house inspector. Check into their credentials if your panel is up to code.