http://www.openbsd.org/faq/faq14.html#D0P3
14.6 - When I boot after installation of OpenBSD/i386, it stops at "Using Drive: 0 Partition: 3" - i386 specific.
This isn't actually an error message by itself, it is the boot loader in the MBR telling you which drive and partition it is about to boot from. The problem is, the boot process stopped here.
There are two common reasons why this may happen: an incompatibility between the BIOS and the OpenBSD MBR, or a drive geometry problem. An example of a drive geometry problem would be if you were to move a drive from one computer to another, update a BIOS or change a BIOS setting on a computer, though it is also reported that it can happen for unknown reasons during install.
Note: As of OpenBSD 3.1, the BIOS compatibility problem should be resolved on virtually all computer systems. However, it is still possible to have a drive geometry problem, so it is still possible to have the system hang after this message.
To fix the BIOS compatibility issue, you must replace the boot loader with one that is compatible with your system. Fortunately, boot loaders are easy to come by.
...usw-usf...