Do you know the ASP.NET skills that do not translate (aka are different) ?

ASP.NET is file system driven, whilst SharePoint is database driven. All SharePoint content and meta data comes from a database, including images, HTML, Master Page, etc. SharePoint provides a framework where components can be plugged in, and as a result these areas are improved out-of-the-box:

• Security model, membership, permissions.
• The UI framework becomes relatively consistent.
• Menus, navigation, and site maps.
• Administration of access i.e., site owners can change permissions for that site – without the need for administrators.

Deployment model is very different:

• ASP.NET has MSI file or XCopy deployment – individual server.
• SharePoint deployment is via Solution Package – but goes cross-site farms.
• Deployment is both declarative in (XML format), as well as in code with Feature and Event receivers.

Tools:

• ASP.NET is mostly done in Visual Studio .NET.
• SharePoint development is split among:
  • Internet Explorer – SharePoint configurations (note: non-IE browsers remain 2nd level and isn’t as good as IE with SharePoint)
  • Microsoft SharePoint Designer – SharePoint HTML page design and customization
  • Visual Studio .NET – custom web parts, custom workflows, solution packages