And no, your salary/rate isn't defined by where the company HQ is. That part defines their price tolerance. The price is defined primarily by how much you ask for and what you can offer in return.
I couldn't agree more. I know a lot of developers that have the mentality to just accept what they are offered without negotiating. It's up to you to get a good price for the value you bring to the company. Negotiation is the best way to significantly increase your salary, regardless of your technical skills.
Patio said it best: http://www.kalzumeus.com/2012/01/23/salary-negotiation/
If you have no other opportunities and no one is offering anything better than you have to accept that. Than they capture the rest of the value.