The OpenStack project is a collection of different applications that provide the ability to run an open-source Cloud provider. Rackspace's offerings generally map to OpenStack projects. Cloud Servers is Nova[1], Cloud Files is Swift[2], Cloud Networks is Quantum[3] and Cloud Databases is Red Dwarf [4]. I'm not sure the OpenStack codename for Cloud Block Storage yet, but I'll see if I can find it.
[1] https://launchpad.net/nova/
[2] https://launchpad.net/swift/
[3] https://launchpad.net/quantum/
[4] https://launchpad.net/reddwarf/