I keep getting asked about the best route to go for mobile development in managed code.

So here are your options as I see it -

1) Deliver it by web browser?

    if you have the luxury of good reliable network connection this may be the route to go.    However tread carefully you have limited/no access to device features like barcode readers,GPS, cameras etc.   This is a nice option if you need to quickly get a solution targeting a wide range of devices to a large audience.    Mobile Silverlight might make this option more more viable in the future.

So if you've decided that a browser based solution is not appropriate then lets move on.   On the assumption that we need to place code on the device using the .Net Compact Framework.

The .Net Compact Framework is a great bit of kit designed to offer the C# or VB.Net developer with an easy route for producing mobile solutions.   However your then faced with the question of how you receive and post back data from your server.   This presents our final two options.

2) Call business logic functionality via a web-service?   This is a great option, if you need have a network connectivity.   You can call web-services on a central server.   However you have to mitigate against situations where the network is not available.    This is also a brilliant if you absolutely need to send updates back from your line of business applications in real-time.   I find this great, if you need to synchronise tasks,  like a forklift operator needs to be called when a pack-house guy has put a pallet down on the warehouse floor.

3)  Use SQL Compact and Merge Replication?    This is great if you need your application to keep on working the whole time and periodically send updates to/from a central server.    However you can't guarantee when the mobile application will be in range of the network so synchronising activities as described in option 2 becomes difficult.   Merge replication is cool but requires a little more thought for how you structure your application as you have to consider just how much data is practical to fit on the device and how long it will take to synchronise changes.

So, I know I've greatly simplified things and you may disagree with my 3 choice strategy with many a hybrid solution.  However this is the process I go through whenever I look at LOB projects.