If you're thinking of homeworking and/or buying a garden office there are hundreds of sites offering you information. Obviously you'll want to hunt around but here are some good first tries. Overall I'd recommend Enterprise Nation as your first point of call. For more details about individual garden offices, you'll need to click on the suppliers' links on the left hand side. Please let me know if you'd like to recommend other sites/pages.
Why work at home?
Why work at home?2
What is a garden office?
Government booklet on planning
A greener way of working
A greener way of working 2
Increase the value of your home
Financial aspects of homeworking
Drawing up a company homeworking policy