Supplied by RSA Security. http://www.rsasecurity.com/
SecurID is no longer limited to a hardware solution, software, hardware, SmartCard and Palm based solutions are also offered.
Offered with a programming API, SecurID can be used for authenication in almost any environment, for example RAS, Firewall authentication, banking applications and so on.
Unfortunately AOL also use SecurID for their CRIS application, which is rather easy to slide into.