I've been in a long distance relationship for 19 months now and so far things are going really well. We've had our ups and downs, but nothing drastically different from a relationship where you get to see your partner every day. Prior to us agreeing to do the long distance thing we barely knew each other, and in some ways I think that actually helped because there wasn't really anything that we were missing out on when we are apart, because being apart is all that we've known except for the few weeks of bliss we have when we do get to see each other.
Communicaton is key, and a tip that I try and keep in mind is to never end a conversation when there's something up in the air. If one of us has a problem about something its key to talk it over right when it appears and nip the problem in the bud. I've noticed that tendencies of jealousy and uncertainty seem to be more prevalant in long distance relationships, but if you talk everything out and set straight your feelings it helps out tremendously.
Long distance relationships are tough, and require a great deal of work and patience and understanding, but I think that the rewards you get out of one are far greater than a normal relationship. Just for the record, my girlfriend and I have been seeing each other since July 2003, and other than a week during that summer, a week over Thanksgiving 2003, and three weeks over Summer 2004, our relationship has been solely phone or internet based. It's tough but with hard work and determination I fully believe you can make it out with your heart intact