QUOTE(Wacken @ Mar 3 2008, 10:28 AM)

You should look up if Belgium allows you to have dual citizenship, meaning that you do not have to renounce your US citizenship to take up Belgian.
Most European countries allow you obtain another citizenship without renouncing the first. But of course a quick call to the Belgium embassy would clear that up.
I don't think that, through marriage, you'll get citizenship in just 6 months. No EU country gives it away that freely/quickly. I'm in the process of getting my Polish citizenship (through parental birth rights - not marriage) and that is going to take about 1 yr. If I were going to get it through marriage, I'd say it would be a couple years, and definitely a residence requirement.
What I didn't know before I filed for dual-citizenship, is exactly what DreadPoolX mentioned. In case there are any problems while you are in Belgium (and already their citizen) the US cant do anything to bring you home safely, because that other citizenship is in "effect" and US is powerless. So I guess in a way dual-citizenship takes away some priviledges... you aren't fully protected by either country.