Phone BW Falkirk on 01324 671217, speak to Brenda (although she might be at the Glasgow office), or go to the top and speak to Linton Byrnie.
If you want to get in at Edinburgh, you need to get on the waiting list, sooner the better. The BW website has costs for the different moorings throughout Scotland, but remember you're looking for the Union Canal, not the Grand Union, which is in England!
The waiting list isn't short, but BW are making an effort to weed out chancers who put their names down years ago but have no intention now of getting a boat.
There are very few residential moorings in Edinburgh, and at the moment no available moorings on the Union canal at all - the nearest is Grangemouth on the Forth and Clyde; but BW will be opening up Leamington basin within the next year or two, and there are plans to dredge a new basin at fountainbridge.