For a simple database with only a few users, perhaps publishing the database to the web might be a good solution. Each user can then access the same database file and create/edit records without worrying about laboriously uploading/downloading/emailing files back and forth.
I've never tried Filemaker's IWP (Instant Web Publishing) myself, so I can't offer any help on the process of setting it up, or the ins and outs of it, but it was just a thought, might be worth looking into:
Go to your Help menu > Product Documentation > Instant Web Publishing Guide
And there are companies that will host your Filemaker IWP database to the web for you in exchange for a monthly fee and this might be a cost effective way to get your database out there for your partners to access.
You could just post the file to a share site for them to download or even set them up with runtimes and just email the data back and forth, but if you take on that approach, controlling the updates so that no data is lost can be a real challenge--especially if two or more users simultaneously modify the same record in different ways.
Anyone have info / recommendation on reliable hosts for Filemaker IWP database? I'm about to hit Google, but inside info [the voice of experience] is probably more useful.
PS to all helpful people: if you are in / visiting London, message me for a thankyou