I simply love Sue Bailey's post on the TwiTip blog about how you should stop asking people to follow you on Twitter. Instead, ask them to talk to you on Twitter.
Instead of just linking to your Twitter account, create a link that puts your name in the message box, thereby encouraging someone to engage with you on Twitter. It's the same as having a "mailto" link for your e-mail. Sure, they'll probably still follow you -- but it surely looks more inviting than a cold "follow me" link.
Just add a line in your e-mail signature a line that says "Talk to me on Twitter" with the link http://twitter.com/home?status=@YourTwitterNameHere
Have you come across other creative ways to get new followers to engage with you on Twitter?
UPDATE 4/15 1p.m. Ok um, perhaps this isn't a good method after all. I just confused Niala by having this link in my e-mail signature -- and she understands Twitter! I guess this kind of link is too techy and unnecessary in an e-mail sig, especially if someone doesn't have a Twitter account. I think for now I'm going to change the link in my e-mail to just say "Message me on Twitter" but have it go to my main account page.