Your questions don't have simple answers. Yes this is possible, but no, it is not a simple thing to set up.
FileMaker can be set up to publish it's data to the web so that users can use a web browser to access the database. If you want to do this, you should carefully read the PDF on the subject that is delievered with the FileMaker software. It can be found in the documents submenu of the Help menu. You can also download the same PDF from the documents link on FileMaker Inc's downloads page. (See downloads link at the top of this screen.)
PhilModJunk, thanks for the reply..
I need to synchronize the Filemaker Db & my website DB, so that the changes in one, also reflects in other..
Which makes the user can pay their bills from anywhere via online..
And using either Instant Web Publishing or Custom Web Publishing can do that for you. In a sense, the changes on the web site are changes to the database so no synchronizing between the two is needed.