How can I write a tool to monitor domain name availability? In particular, I am interested in monitoring availability of a domain which is in PENDINGDELETE (or REDEMPTIONPERIOD or REGISTRY-DELETE-NOTIFY or PENDINGRESTORE or similar ) status after its expiration date.

Any suggestions or more information about the PENDINGDELETE and similar status are also welcome (what is the time frame till which it can remain in this status, etc. I usually don't see a fixed pattern or even consistent correlation with expiration date and this status).