I have 6 AC websites and need to know if I have to get 6 individual accounts to make the feed work or can I just use one main account. I keep getting error messages that the domain name does not match.

Any thoughts, I am very new to all the cool free stuff in the Google Webmaster and since sales suck right now I need to pull out all the stops. 

Any thoughts or ideas would be helpful. I have a lot of tweaking left to do to get our sites where they need to be.

I will watch here for other answers.  But until then, here's my experience:

 I have 5 AC websites.  As a test, I started two accounts for two stores and have them both feeding to Google Base.  My main store is doing very well with Google Base, and it always has.  But my second store, because my products are identical, isn't getting any extra business.  When anything pops up for one store, it pops up identically for the other and it's obvious that both stores are owned and run together.  Since my catalogs are exactly the same, I don't gain any benefit that I can tell.  I have not set up the other two stores because I don't think it's worth the bother. 

I have many websites as well, although each has a primary focus, the entire contents of the catalog can be found on each. We have had to split up the inventory to have certain items int eh feed for certain sites. This way we get all of our sites within Froogle, with the products that are most relevant to that site. We had no luck with each individual site submitting all 50,000+ products to froogle.

We did however build our own feed management system, so we are toying with using unique titles and some other info in the feed for each store to see if that allows us to submit the same product across multiple sites

I have 2 sites and Google does not allow the same products to be listed by two different websites if they are owned by the same company, individual, etc. In order to do that, both of the sites must have completely different product lines. I was thinking of taking one site and using it for accessories as well as apparel. Currently I waiting for it to rank as I want it to, then at that point I will make the changes, notify Google and get their blessing on listing both websites.

I have to assume that they monitor this via the DNS server settings, or IP addresses, not sure. BTW, they were very nice and explained why they have that policy.