Take a VERY Full wallet or a very empty credit card with a big limit!!
It's not cheap!!!
Try
Horizons unlimited for info there should be some good stuff there
I'd disagree with the expense side of things... yes it can be, but if you're smart you can do it cheaper.
We've been out there a couple of time, first a long weekend to Reykjavík where we hired a Landcruiser which cost between us what a single "golden circle ticket would have cost". We did a load of driving out and able from there and saw as much if not more than the tours without all the people. It was a good few years back, but I honestly didnt think Reykjavík was any more expensive than any other western capital city.
The second time we went out we flew to the north, picked up another Landcruiser and toured around the north, east and west, driving back to Reykjavík... the north is a lot more expensive and there arent as many options... we ended up spending something reduclous like 60 quid on two very medioca pizza and 2 beers, after that we bought stuff from local supermarkets and cooked for ourselves at various place.
Iceland is a really amazing country, I've really enjoyed myself both times we've been and would definately go back.
it's well worth working out what you want to do and picking your time accordingly, one of the things I wanted to do was some of the inland routes, we got lucky as they opened up towards the end of our trip, but we could have easily missed them
There is a ferry from Dk which stops off at the Faroes and is a 36 hr crossing. The cheapest crossing with a m/c is 568 euros return. It's a 1000 boring miles ride to Dk for me but it's looking favourite at the moment.
the last time we were out there we met a couple of guys who'd done just that. One on a GS the other on an RT (that had sadly been dropped a couple of time). Just checked, our last trip was June 2005. The guys we met seemed to be having an excellent time, but even in June the North is bloody cold

didnt notice it too much in the south
edit: the attached pic is me trying to look shame faced at the state of the rental car... really doesn't work when you done mean it
