From Wikipedia: RSA SecurID is a mechanism developed by RSA Security for performing two-factor authentication for a user to a network resource.
I just read about this device, and it seems interesting to me. However, I'm not sure how (or even if) software (networked or non-networked) can utilize this method of authentication.
I'm making this a community wiki post as this isn't a specific question, but a general overview of addressing authentication with SecurID and similar technologies.
Verisign's OpenID provider supports such tokens (sold at a discount by EBay and PayPal), which is certainly the easiest way to get started using dual-factor authentication for web applications.
My company, WiKID Systems, has a dual-source two-factor authentication system. In addition to radius, ldap etc, we have a very simple API called wAuth and packages available in PHP, Python, Ruby, Java and C#. These 'network client' packages are LGPL so you can put them in open source or commercial licensed software. You can download here. It would be pretty simple to do others too.
Also, we have an open source version of the software token, so you can embed that if you like and you can really see how the system works from end-to-end.