Research the IMPORT script step. The types of DOCUMENTS can be read by Filemaker are described.
Research web publishing (custom web publishing using xml/php or xDBC). You can often accomplish what you can with other databases using a web interface.
Research plugins designed specifically for use with Filemaker and web services.
-- sent from my iPhone4 --
also - experiment with creating a webviewer, naming it, then using set webviewer with option 'goto url'.
this is a gofriendly , noPlug in method for making GET calls to a webservice.
Then, experiment with GetLayoutObjectAttribute , object type "content" as the means to pulling ur responses from the webservice back into filemaker.
good luck - lots of fun to be had sneaking out of filemaker thru the webviewer.