You will find below links to useful vendor-neutral URLs about Enterprise mashups, RIA, Web 2.0, Cloud Computing, etc. Tell us if you know other good references that should be added here.

Wikipedia

• Web 2.0
• Mashup
• Mashup Enabler
• Composite Application
• Rich Internet Application (RIA)
• Adobe Flash Builder
• Cloud Computing

Blogs

• Michael Ogrinz' Mashup Patterns
• Dion Hinchcliffe    (mostly about WOA, but also deals with Mashups)

Books

• Mashup patterns, by Michael Ogrinz
• Mashup: strategies for the modern enterprise, by Jeffrey Hanson
• Pro Web 2.0 Mashups, by Michaal Lee

Mashups portals

• Programmable Web
• Mashable
• Web Mashup
• Mashup Awards
• StrikeIron
• Web Service List
• Web Service X Net

White papers and articles

• Mashup et applications composites, by Useo (in French)
• Enterprise Mashups, by Larry Clarkin, in Microsoft Architecture Journal