Hi All,
I started off on Babelfish when I first started to learn Spanish and found that at least a few years ago it left a lot to be desired. It's greatly improved now but it still makes some mistakes.
I agree with the advice that suggests you get a dictionary, not to trumpet these very good forums but
www.wordreference.com has one of the best online translation dictionaries I've ever seen.
In addition to that, a good verb conjugator is an absolute 100% must-have if you're serious about trying to translate it yourself.
I bought a little application called "Verbix" about a year ago and it's great. I believe they also have a freebie verb conjugator on-line too:
http://www.verbix.com/webverbix/index.asp
Disclaimer: I don't work for either company (I'm from Australia and have a Mexican girlfriend if you want to understand the Spanish motivation) but these tools helped greatly.
Enjoy!