I'm puffing away happily and safely on my Model 510 e-cig as I type this reply!
I have essentially* quit smoking, after 31 years, since July 4, 2009. I can breathe again!
You can learn all about e-cigs here:
http://www.e-cigarette-forum.com/forum/
Beware of low-quality e-cigs sold on radio and TV. Educate yourself BEFORE you buy!
*I say "essentially" because I occasionally smoke my pipe, enjoy a fine cigar now and then, and still, I must admit, smoke an occasional cigarette-not even one a day on average.