On a 32-bit Windows, you can access accdb files through the ODBC driver which is available for free at 2007 Office System Driver: Data Connectivity Components. (If you installed Microsoft Office 2007 on your machine, you already have the driver as well and don’t need to install it.)
Unfortunately this hasn’t been possible on a 64-bit Windows, because such a driver didn’t exist for a 64-bit environment. Now it seems that Microsoft is working on it to release a 64-bit version of Office 2010. It is still in beta status, but may be useful. The download link is here. 2010 Office System Driver Beta: Data Connectivity Components. They released the official version now. See Microsoft Access Database Engine 2010 Redistributable.
There is a little more information in Microsoft SQL Server Support Blog : How to connect to file-based data sources Microsoft Access , Microsoft Excel and Text files from a 64 bit application.