Here's one person's experience, along with a slide show of other sneaky Internet scams.
This hit closer to home for me when some of the quilting teachers listed as Libby Lehman's friends were hit up, supposedly by Libby who was stranded at a conference and needed funds to get home. (She wasn't, and she didn't.) To make things even more interesting, the scam hit a second level when a girl from New Zealand claimed she'd sent money, and now was dunning to try to get the funds reimbursed! (Also not proven.)
The moral of the story: Do NOT believe e-mails from anyone claiming this. If you know them well enough to want to send money, call them directly first. No matter what.