I'm not a Scot but I play one on TV!
![Wink [;)]](/emoticons/emotion-5.gif)
Actually, I play a Scottish pirate and an Irish nobleman at several Renaissance faires in the U.S. My dialect has been good enough to fool many visiting Brits and last year I fooled several Scottish girls working in the U.S. as au pairs - my proudest moment! Both the girls and the Brits asked if I was from Edinborough and one guy (from Wales) called me a "wanker" when I said I was a Texan moved to Minnesota 18 years ago!
I tried the dialect CD previously mentioned but found it wasn't much use for me. Initially my accent was over exaggerated (as are my characters) and I described it as a cross between Groundkeeper Willie from the Simpsons and Mike Myers father in the movie "So I Married an Axe Murderer". I wanted something more realistic so I watched "Braveheart" quite a few times and found a dialect site on the web that played distinct pronunciations of certain words (it's no longer online). To my ears the Scottish dialect is more guttural, harsher than the Irish which is more lyrical and playful (NOTE: That's just to my ears!) but I like the Scottish dialect better. My heritage may help too as I'm half Scottish and half Irish by birth.
In Braveheart pay attention to actors like Brendan Gleeson (Hamish), James Cosmo (Campbell - Hamish's father) and especially Angus Macfadyen (Robert the Bruce). While Mel Gibson has a good dialect and worked with a good dialect coach his native accent is Australian (though New York born) namely, New South Wales, Australia. The others are native Scots or Irish.
Also watch a movie called "The Matchmaker" that was shot on location in Ireland and listen to David O'Hara (Sean Kelly) or actually, just about any of the locals as they are all from the area. For those of us who cannot afford a quick trip to Scotland or Ireland these help a lot. Also check and see if there are any Gaelic classes in your area. I know we have them here in Minnesota and there are many in the northeast areas like Boston.