For the doorbell and button i’m using a Home Easy HE-306 doorbell with a RFXCom RFXtrx433 to receive the push signal from the doorbell.. but as you’re not likely to be in the UK that probably wouldn’t work for you.. but i believe something like the insteon IO Linc wired to the doorbell button would work as well.. or google for x10 doorbells.. i seem to recall there’s a lot of them out there.
As for the front door camera i use one of these:
http://www.ebay.co.uk/itm/Security-Tact ... 2327d23600 The image isn’t great but it is good enough to see who’s at the door.
As for scripts most of it is trigger based with action groups rather than scripts.. so if the doorbell is pressed it’ll immediately trigger the doorbell and set the PiP on my tv to the front door camera (using a Cynical Cache GC-100). It also sets a delayed schedule to re-ring the doorbell after 45 seconds if the front door is not opened. If it’s opened the DSC alarm sees the zone open, and that activates another trigger that removes delayed actions for the doorbell.
Also using SecuritySpy as soon as the door bell is pressed it starts recording an image of whoever’s at the front door and i hope one day to setup some kinda script to take a jpg of that and email it to me if i’m not home.. but i’ve not got that far…. yet