I can't seem to get an answer to this question ..

I have an AE tied to involvement as gastwissenschaftler. I've been here since December '04. When I abmeld & leave Germany I'd like to travel a bit here and in Europe before going home.

As an American we get "90 days without a visa"

Can I simply leave Germany & travel around Europe for up to 90 days at that point. (ie when does the 90 day clock start .. do I need to leave (Switz?) & come back in right before I abmeld? to start the clock)

Another fine point .. I have a letter stating my "beschaftigung" with the Uni through August...if I abmeld in May from my town does that automatically dissolve my AE. I actually remain involved and need to travel to the Uni several times during the summer. My town is in a different Land than my Uni as well.

..help please

This is a tricky question. But I am pretty sure who should know these visa things in detail - it is Bundesgrenzschutz. You can try to locate the nearest BGS(=Bundesgrenzschutz) office in your city and ask the by phone - even better go to nearest airport and find the BGS office and ask them. Not normal Police but BGS (border control). They have written on the shoulder "Bundesgrenzschutz" and drive cars with plates "BG" :-) .

I have made good experience with them, very helpful indeed.