I discuss it right up front. I do my best to bring it up politely, but I do bring that up along with time-off, on call duties, and a few other important things. I let the interviewer/recuiter know that I don't want to waste their time, as I am employed and won't be able to consider anything too far below what I am currently making.

I have had quite a few thank me for being so open. I had one who said that they don't discuss salary until the final interview....I made it to the final interview and got a job offer letter...had to turn it down as it was way below what I was currently making ($30,000 less). I made a counter offer, but they refused that and so I sent them my letter thanking them for their time and I let them know in my response that they could have saved themselves a lot of trouble and possibly found the right individual if they had discussed salary from the beginning.

So, I believe it is proper to bring up salary from the beginning....but you need to do it politely and let the company know you are trying to make sure their time isn't wasted.

-SQLBill