i'm interested in getting a new Tablet-PC but i have to wait for the new Android 3.0 version Honeycomb that Google stated is the one for tablets
so i wanna know if i get a tablet with version 2.2 or 2.3, can i upgrade to 3.0 later on? or do i have to get one with 3.0 already on it??
It depends on the tablet. Which ones do you have in mind? Regardless of the brand/model you are thinking about, I'd maybe get in touch with the manufacturer's support team to ensure that it is eligible for an upgrade when Honeycomb comes out.