[Robbie Mackay, Ushahidi] 1. SMSSync will simply post the received messages to your server (or whatever URL you configure). You would have to parse the status/category/etc into a post yourself.
SMSSync just uses the SMS services available on the phone, so usually standard SMS charges apply, both for you and the people posting SMS. If you need anything different then you'll have to negotiate with your mobile provider
Same as 2.
SMSSync doesn't really care what your server runs, as long as it handles the HTTP POST requests that SMSSync sends to it