That's a pretty broad question.
1. What radio are you talking about?
2. Data rates enabled?
3. What kind of space? Office? Office with cubicles? Warehouse? Warehouse with racks?
4. How high is the WAP installed?
5. How is the WAP installed?
With all data rates enabled, and let's say you are in the middle of a wide open space (like a farm), you can pretty much get 802.11b up to a range of about 40 metres.
