Never give out your current salary. That's not what this interview is about. Employees often forget that the entire 'getting a job' thing is one big negotiation when you boil it all down. It's not about 'being a team player', 'getting your foot in the door' or 'doing what's best for the company.' It's simply about 'here's work that needs to be done, here's why I can do that work for you and here's how much $$$ I'm willing to do it for and how much $$$ you're willing to pay for that work to be done.'

What your current employer pays you is none of their business. It's about what this company is willing to pay me for my work. The only way I'd give out my current salary is if the company tells me what their end budget is for that particular position. Otherwise if they insist or find that it is a turn-off, they aren't worth working for and they can go pound sand.

But keeping with the negotiation theme, it's perfectly okay to give your salary expectations because that's about half of what you're negotiating. It's just that if you want to win the negotiation, your goal is to get the company to tell you what their salary is for the position *first*. It's just difficult to get that because most companies know that is a way to lose a negotiation and that they have more leverage in the situation.

When I tell them my expectations I tell them a little more than what I am looking for. If I'm looking for $100K, I will say to the effect 'I'm looking for around $105K, but I would be willing to negotiate in the end. Am I somewhere in the ballpark with that figure?'

If you know your market and your market value they may come back and say 'well, that's a little higher than we were expecting.' And the reply to that is just to reiterate that you're willing to negotiation if the opportunity looks like the right fit. If they say that is well outside their budget then it wasn't the right company for you and just move on.

But in the end, you had every right to not tell them your current salary. It's none of their business.