If you are thinking about managing one, you should be ready with a few set of things

1. Specifications. Many companies overdo the cost-cutting practice, by following an iterative process, wherin the specs are made as they come into picture. This  becomes a major issue, and mind you, not later, probably a month into the work.
2. Timings You may have to take care of weird timings. So before taking up a project, I think you should decide on who should work their nights out, you or the offshore dev team.
3. Boudaries both legal and international It is a very sorry fact, but there are cases in many offshore countries where people did not possess the morality to respect legal boundaries and went into piracy, and in other cases, broke someones code to write some for you. Beware and make sure this doesnt happen. Along with this, it is highly probable that you will have to travel atleast once to meet up you offshore team, and from some i have heard its not an easy process for a US citizen to travel to a third world country on a business visit; i may be wrong, but atleast its a cause of concern. Dont forget to bring your spouse, we are very good hosts by nature.
4.  Processes  You should define the processes first, its a personal experience that things progressively get from bad to screwed up, if you rely on daily mails only. Major things that will help you would be Continuous Integration (something like Cruise Control.Net) , TDD, Source OffSite(or some other), because these are the only things that will help you manage the direction, and administer the growth.

Ofcourse there are many other things, but mine is a perspective of a small offshore company working with consultants for small companies in the US, working on products. Things are majorly different for big companies and the services industry, and really, I dont care for them.