Not sure what your ISP was referring to FileMaker having FTP capabilities. I seem to think they were just telling you that you could ftp the database file around for individual use on various computers. Unfortunately that would not be a shared database and your data will be out of sync.
FileMaker database hosting is not really all that expensive these days. MacUSA.net hosts databases for $16.95 per month or $169.00 for the entrire year.
Thanks DanMC, am opting for a Filemaker hosting package. Am I right in thinking that I could use IWP to allow my remote worker to access the hosted database, whilst I could connect to the hosted database with Filemaker running on my PC at the office (ie - not using IWP)?