This is a small collection of screenshots and hits on what you need to different to turn your SLES 10 installation into an OES 2 installation. To make myself clear, OES 2 is SLES 10 SP1 with a software addon. The most important difference between these two is that OES 2 most important feature is the support for eDirectory out of the box.

When installing SLES 10 SP1 you get the chance during the installation process to add an addon media to the installation:
After checking the checkbox and selecting the addon source you can add the correct CD to the drive:
After accepting the EULA you'll see the extra installation source:
If you see this correctly you'll get the chance to install Open Enterprise Server services to the server.

During the software selection you can change which services you need to install. In my case, a groupwise server for a second domain, it was this selection:
If you are, just like me, installing NSS you have to consider a lot about partitioning. This Novell documentation can help you on your way. If you have multiple disks don't configure anything about NSS or EVMS, and let NSS reside on the separate disks.

By default SLES 10 SP1 still uses reiserfs as it's file system. Personally I think reiserfs is a great filesystem but the creator is sadly in jail. Support is hard to get, so for production servers I select ext3 nowadays days. There is another thing I change on my partitions, the access time. This speeds up the file system a little:

Near the end of the installation you'll have to configure OES to join an existing tree. Of course you can create a new tree, but this article joins an existing one: