T- Test output

I am conducting an independent T-Test in SPSS (users and non users) against a range of independent variables. I now have found significance in one of my variables (perceived compatibility) the results are; t(49) = -3.357, p=.002.

Am I right in thinking that because my t value is negative (-3.357) that I should give the explanation along the lines of:

"These results suggest that perceived compatibility does have an effect between users and non users. Specifically my results state...when someone is a user they will have high perceived compatibility ?

Any help clearing up what "t= -3.357"actually means would be much appreciated as through trawling through my text books and the internet hasn't yielded me an answer! Also, what would it mean if t = (positive) 3.357?