TS
Simply check out:

http://www.subscriptiondata.com/
Download the demo and check out one of the xl example files.
(Look similar to the one's on offer here,surprisingly).

Then there are options only you can decide upon to start coding.
To start coding, it's popularity is increasing and it's no secret but check out
www.realbasic.com and download the demo then decide your options.

I guarantee you in 12-18 months if you *realy* want it, you will have your own database.