I need create/modify an application to operate in an occasionally connected manner.

The app needs to run on laptops that may or may not be connected to the internet at any given time.

Each laptop to will need to download a subset of records from the central database (MS SQL 2000) and sync any changes back to the server every day or so.

The data is sensitive so it needs to be secured in some way.

After deployment the app will likely require many updates and I would like it to be able to check for updates periodicly and apply updates.

I am used to working in a LAN enviorment where the database is always available and I could use any tips how to approach this.