It's a great show to watch just to hear the characters speak in Manchester accents, some of which are so thick that Americans could use subtitles. I often pause and replay bits to try and work out what they're saying, and sometimes I'm stumped. But like any unfamilar English speech, there's plenty to amuse the amateur linguist -- expressions like "gobshite" and insults like "you gormless twat!" The Manchester accent is, according to surveys, the least popular regional accent in the UK, but I love the oddity of it -- the way the ending 'ee' sound in words like 'security' comes out in between 'securiteh' and 'securitay,' a bit like how Cartman pronounces 'authority.' One of the characters, expressing lesbian lust says "she makes me funny go all wavy" and I think she's actually saying 'fanny.'
Anyway "Shameless" is wickedly addictive, and there's a lot of it -- 3 seasons of 45 minute shows, plus a 90 minute christmas special, and there's a 4th season in production for 2007. It has been on BBC America but I don't think it's showing just now.