well best way to hear music is to download it...get limewire coz its quickest n is easy to use.
in terms of ska, depends wot u want really...the best way to get into ska is to listen to the new stuff...
the best in my opinion are:
SUBLIME (although they are reggae not ska but they're amazing in every sense of the word) - the classic songs r "santeria", "smoke 2 joints", "40 oz to freedom" and "what i got" i guess.
catch 22 - "keasby nights" is a catchy song (haha wot a pun)
streetlight manifesto - well my fav off that album is "here's to life" although the whole album is absolutely spectacular
rx bandits - yyyeeeyyy am off to see them in 15 days

err listen to "lost", "Secret agent man (SAM)" or "progress" coz they're all great songs
Mad Caddies another great ska band...ummm "shut the door" is a good song, so is anything by them really just download wot u want
less than jake always good but uv probs heard loads by them anyway
lol hope that gives u some ideas