I'm planning on developing an Apple Mac application which will collect hardware information from the host Mac and also installed software info. The hardware and software info will be collected in an encrypted XML file and then posted back to a website. The application should run as a "service" or background process on the Mac and can be configured to collect the data on a frequent basis defined by another encrypted XML config file.

I've done plenty of Windows based software development but never on the Mac. Can anybody point me in the direction of any useful info on how to develop on the Mac, collect hardware and software info, export to an XML file, file encryption and packaging a compiled app to run as a service? Is either Objective C, Cocoa or Ruby a possible option?

Many thanks for your help in advance!