I know that DLR will be released together with C# 4.0, but I don't know when that will happen. In the meantime if somebody wants to use DLR in a production environment (nothing hardware-real-time-system), should he/she consider postponing it until C# 4.0 comes out?
What I'm asking: is the existing version 0.9 supported by Microsoft?
I presume that you will be using languages that rely on DLR. Right now IronPython 2.0 and above (2.6) are production ready. IronRuby is reaching 0.9 version and soon it will hit 1.0.
There is no need to wait for C# 4.0 to become available.
The hosting API to integration with DLR based languages are solid. We have been using DLR in production environment.