There appear to be a number of possibilities in your area.
Our tandem (now 6 years old) is an Apollo. We bought it after hiring one for a weekend, because it was not going to break the bank. It's been a great first tandem and has stood up to everything we have thrown at it, including a trip to Europe, several tours here in NZ, mountain biking, commuting and child transport. I now have kiddy cranks and ride it with my 4 year old son.
Most good LBS can get a tandem of some sort for you. If you can hire or borrow one first to see if you and your stoker enjoy it, that would be good. If you go ahead and buy a tandem don't get a high end one for your first tandem because the novelty might wear off, you can always update if you get hooked.
Like simsi our tandem is an Apollo, which I've modded with 40 hole Velocity rims, drop bars, a 52 tooth chain ring and a 11/27 rear cassette. I could do more, but with 2 roadies, a MTB, 2 Raleigh 20 bikes and more to play with, it will do for now or I'll update later for a better bike.
Myself and a few others have bought their tandems from Mel at http://www.tandemseast.com/
We have a custom Co-motion Mocha Co-pilot that we have put 10,000kms on since we bought it in 2005 and couldn't be happier. The exchange rate is pretty good at the moment too.
The difference between the cheaper tandems and a good one is vast.
Locally, Canondale sell the odd tandem. I have heard of shops doing reasonable deals on them.