I would like to create a database where select data can be synched from handheld devices (probably running windows mobile) to the general database. An example would be a payroll database where off site supervisors can enter employee time into a windows mobile handheld, and then synch their devices to the main database where the employee data is uploaded.

Is it possible to use a mysql database for such purposes? Would it be a relatively pain free job for a consultant to do?

If you are wanting to sync with windows mobile then you would simplfy your life by sticking to the Microsoft stable and use SQL server. However there is no reason why you cannot talk to any db backend. I just think in design terms if you are going down the route of a local db on the PDA then it makes sense to stick to the same family of db products.

I suspect there will be more examples of people using SQL server for that task than MySQL, you will almost certainly have to do a bot more work working out the synchronisation strategy from the PDA to MySQL than SQL server. And I'd guess the skills will be more transferable staying with SQL server