The ICC specification is widely used and is referred to in many International and other de-facto standards. It was approved as an International Standard, ISO 15076-1, in 2005.
The current version of the specification is Version 4. Color management products are now mostly v4 compatible, and vendors are strongly urged to upgrade their products to be compatible with the v4 specification and its Perceptual Reference Medium Gamut. The v4 menu above provides links to documents and resources on the v4 specification, including a summary of the main advantages of the v4 specification, and the reasons to use v4 profiles in colour workflows.
The v2 specification is still supported and recommendations on making v2 profiles that can interoperate in v4 workflows are provided.
Profile creation software that will produce profiles that conform to v4 are listed in the Profiling Tools page, and applications that will utilize them are widely available.
This site contains information about the ICC specification and about color management generally!