Due to the current economic downturn, it is increasingly difficult to find funding for just a MS (without the expectation of continuing on for a PhD) in the US. More people are going back to grad school, and schools are getting less funding. When I visited schools that I had been accepted to, each one (all of the big name ones) emphasized that they only had enough money to fund anywhere from 3-6 people at the Master's level. At UT Austin, they used interviews during the open house to determine who received that funding. At Stanford, funding was based mostly on GRE scores, LORs, and GPAs. The UC system is in particularly bad shape if you're an out of state student. I found that at both UCBerkeley and UCSD, you cannot get full funding for your tuition fees unless you are an RA, rather than a TA. TA positions are also increasingly difficult to get, because schools will have PhD students do it, or they'll have students that are continuing on from a BS (this was particularly true at UT).
I have some friends who applied for grad school five years ago, and they were shocked at how scarce funding was. UT Austin is known for having money in my area (structural engineering), and it used to be that if you were invited to the first open house, you were guaranteed funding.
That being said, I did luck out and get offers of funding at three schools (out of the six I applied to). One of these was only half tuition, but the others were full tuition + stipend for either RA work or TA work. I know that I got funding at one of these schools based on my interactions with professors (I was funded through a particular professor, rather than the program).
Do your research to figure out which programs have a history of funding some of their MS (I'd check the stats on this website first). I don't know if you're interested in doing research during your MS, but that will definitely help with your application. You should also check deadlines for the schools you're interested in, because often there will be a separate (and much earlier) deadline for funding.