Unfortunately it's not something FreeScan can handle right now. It's one of the few holes it has - it doesn't do LBS, nor any of the location-based alerts. So far Assaf hasn't had this one in his high to-do list.
You might try BcTool, ProScan or ARC-XT to see if either of them support LBS. ARC-XT can be purchased via Scanner Master...and you can find links to these packages here...
Uniden DMA Software Support - The RadioReference Wiki
The only way he's likely to get something started on this is if enough people start asking about it. 'nuff said...
HTH...Mike
[edit] If you want to read up on LBS, I would check out the description in the Easier to Read manual, and this extensive article - with cross links to the Uniden TWiki that has a lot on this subject - in our wiki
Location Based Scanning(LBS) - the RR Wiki