Back when IWR's staff were tuning in and dropping out at Uni, JANET was a pretty new thing, and the National Centre for Super Computing Applications had developed a program called Mosaic that looked pretty interesting. Things have got a lot more complicated than they were in those early days, and allowing staff and students access to resources is a more complicated business.
Enter, stage left, Eduserv, the not-for-profit public sector services organisation. Eduserv has launched OpenAthens, a cheaper and easier framework for instititions that want to get access to UK Access Management Federation resources protected by internet2's Shibboleth, and keep access to Athens-protected resources. The aim, effectively, is to enable institutions to share and secure resources easily. At the moment, OpenAthens is not a huge deal - after all, JISC has made it possible for institutions to get free access to information protected by Athens and Shibboleth until July 2008. But after that point, it's a paid for game, and OpenAthens provides access for between £1000 and £10,000 per institution. The deal here is economies of scale - Eduserv does the development and offers it to many.
Eduserv reckons the bill is cheaper than Universities and the like going out and developing their own framework from scratch, but of course there are a couple of other options out there. The main two are Microsoft's  CardSpace, built on .Net (read a quick summary here) and the OpenID, which is a bit more, well, open, than Microsoft's offering. But the interesting thing about OpenAthens is that it's pretty much Switzerland - it'll play happily with OpenID and Shibboleth, yet be cheaper to implement than doing it in house using .Net framework or OpenID.