Smaller publishers are great about being responsive to ARC requests (though you'll often have to request one book at a time), as are authors--but it's tough to get the time of day from the larger publishers. I have a bit of web and print presence as a reviewer, plus some other relevant credentials, but I have had tremendous difficulty getting anyone at the bigger houses to pay attention to my requests to be put on their reviewer lists--or, if someone does respond, getting them to honor a promise to provide ARCs.
If you check the websites of the larger publishers, they often require you to fax your request for review copies. Forget about getting any kind of a response this way; I've tried it, and it doesn't work. Where I've had success, it's the result of getting a contact name in the publisher's publicity department and approaching that person directly.
I don't mean to sound discouraging or negative--you can get results if you're persistent. It can be a frustrating slog, though.
- Victoria