How to integrate telecommuters in an agile process?

I'm sure that all of us have had to deal with telecommuters at some point in time, and I'm facing a situation now where my new project will have a "core" group of office workers and some off-site telecommuters. Not wanting to repeat past mistakes, I'd really like to know what ways people have tried in the past to effectively integrate telecommuters in an agile process, namely scrum.

My first fear is that the telecommuters will be the first ones to break the "daily scrum" routine. And, as human nature often goes, once that gets broken, it's hard to resume and get people back on track. Scrum recommends enforcing small, fun "penalties" for people missing or being late to the daily scrum, like donating a few bucks to a jar which would later be used to buy a case of beers for the end-project party or something. This is obviously something that would be difficult to enforce online.

The other big problem with telecommuters is the "out of sight, out of mind" problem. Aside from using webcams/skype/teleconferencing, what other tips do people have for keeping the team as closely knit as possible?

Also, what about dealing with telecommuters from different timezones? At the moment, we're lucky enough not to have this problem, but it's definitely a possibility at some point in the future. How have other teams dealt with this problem?

Solution

Set the ground rules upfront. Don't be wishy-washy about them.

You've probably eliminated the "I got stuck in traffic" excuse for missing the meeting or whatever when they're working from home (or a satellite site) and so there's no reason to expect less out of them.

Take advantage of technology:

Use IM. We use it here and it is great for 'reaching out and touching' the guy four states away. Make it a requirement to be available via IM.
Use other tools to help break down the barriers. It'll depend on your situation.

If you're having the daily meeting, it should be clear to everyone that you're going to be asking the questions:

What did you accomplish since we last met?
What are you going to be doing today?
What's in the way that needs to be moved?

Just because you can't see Matt in his cube doesn't give me a right to be lazy or unproductive and unresponsive. It's like dealing with my kids - let them know the rules and what is expected, then nobody can claim ignorance.