Microsoft has come to help you out. They have released an updated version of their Developing SharePoint Applications guidance. Coming from the patterns and practices group it offers examples and information on building collaborative applications that include integration with Line of Business applications.
Learn By Example
There are three components to this guidance:
- A Guide: Documentation that shows you how to integrate LOB systems with SharePoint, how to upgrade SharePoint applications, how to use the patterns and designs, how to create and deploy content through SharePoint and more.
- A reusable Library: A set of reusable components, including AJAX, workflow, configuration and features components.
- A reference implementation for a Partner Portal Extranet: This is an actual SharePoint implementation showing how to build a partner extranet with features such as LOB integration, flexible navigation, publishing capabilities, collaboration sites and more. It is designed to show how SharePoint can be implemented for secure, scalable applications.
SharePoint Guidance - Partner Portal Extranet
Guidance for Experienced Developers/Architects
This is the second version of this guidance. It includes all components of the first version such as the Training Application Reference Implementation (designed for basic SharePoint capabilities with WSS3.0).
To use the reference implementation you need to have at least Windows 2003, Microsoft .NET Framework 3.5 and Visual Studio 2008. All code is in C# and ASP.NET.
Although you don't necessarily have to know SharePoint really well to use this documentation and reference implementation, it is expected that you have a good degree of Microsoft development experience.
Keep an eye out on the Codeplex Community site for early drops of additional SharePoint guidance.