I can second this. I have two remote cofounders (~2 hours away), both are decade-long friends. So far working out well, but we've had instances where one of us

I can second this. I have two remote cofounders (~2 hours away), both are decade-long friends. So far working out well, but we've had instances where one of us needs to come up and stay with the other for a business week or two to get through some of the tougher collaboration pieces. If you already have a good, trusting relationship and high work-ethic then this can work pretty well via IM and email. I've also worked a few years telecommuting myself, so I've learned a lot of the tricks to maximize the efficiency of that sort of situation. Using things like Jing, GoToMeeting, daily phone status meetings, and, lately, Chatterous, have helped us keep the communication efficiency high for our startup. Definitely not for everyone, but it can work pretty well if you try hard.