在ASP.NET中从SQL查询中填充XML的最佳方法?

I need to create a service that will return XML containing data from the database. So I am thinking about using an ASHX that will accept things like date range and POST an XML file back. I have dealt with pages pulling data from SQL Server and populating into a datagrid for visual display but never into XML for delivery, what is the best way to do this? Also if an ASHX and POST isn't the best method for delivery let me know... thanks!I need to create a service that will return XML