These days team are split up geographically. How does a good manager cope with this challenge? Start by putting your expectations in writing. This is advised even if you have local employees.
Next you should offer a bonus to those who finish their tasks ahead of time. There should be some incentive to stay on task when you are physically away.
I hear that you should also have a short talk on a daily basis. This is like the daily team standup meeting. Personally I hate these. They seem like a waste of time. I find that they usually are never short.
Require your developers to have a predictable work schedule. Even if they are at home in their pajamas, they should still be working regular hours. Finally put some short milestones in the schedule. This also applies to local workers. It allows you to detect problems as early as possible.
A Little Bit of Crypto - I have been trying to figure out to "collision resistant" some of these standard hash functions are. It is a tough concept to get my head around. I figure...