I'm very new to Sharepoint and I am just wondering if it's possible to somehow use data from an external database as a List that users can select from within a form. How much extra development does this involve?
Essentially we have a different (non sharepoint) site that allows us to set up projects. Once a project is set up I would like the project code to be usable from within workflows, forms, etc.
If you have MOSS Enterprise, you may want to take a look at the Business Data Catalog (BDC). It allows you to bring external data to SharePoint. Supported inputs are either a database or a webservice.
http://msdn.microsoft.com/en-us/library/ms563661(office.12).aspx
After you have set up the BDC, you can use the business data field to use that external data as metadata. That way, you can make decisions in workflows based on that metadata. If you want to play with the BDC, get yourself a decent tool to generate the application definition files (xml), because creating them manually is cumbersome.
Consuming external data in forms is even easier. It doesn't require the BDC as you can use databases and webservices directly as a secondary datasource in InfoPath.
Another option (if you don't have MOSS Enterprise) is to create a timerjob that keeps a list up-to-date based on the projects found. Of course, this is not updated in realtime and requires some programming.