Lately I was trying to deploy Meteor application to Heroku but current version of buildpack is outdated, so I've spend some time to make it work with newest Meteor release 0.8.3.
You can find buildpack repository here https://github.com/jagi/heroku-buildpack-meteor. And if someone needs movie showing the whole process step by step, please go here https://www.youtube.com/watch?v=boeTv3527E0 Hope it will help you :).