How difficult would it be to develop a flash application where users can
customize their own images and have the result be uploaded to a server.
Specifically, this would be an application where a user creates their own
logo, with the ability to upload their own background and choose from a list of
borders, all previewed in real-time.
I have moderate flash experience. I'm not too good at the coding though. Any
toturials on this?

thanks for your help.

Hell0 --

You will have to create custom objects and methods that utilize the Flash
Dynamic Drawing API.

You will also probably have to set your movie up to read in and send out
actionscript that builds and alters XML data trees on the fly via Actionscript.

You will also want your dynamically generated XML object to snap into a
server-side PHP script that will save the XML properties to a mySQL/SQL
database.

You will then want PHP scripts that can recall and reload previously
manipulated Drawings within your Flash movie when requested again by your users.

You will then have those PHP scripts repopulate the XML object and return the
new datasets to the Flash movie via Actionscript (probably into a custom
component which you will have to build and configure properly).

--jmac