I self host Windows 7 everyday; except I have the luxury of more recent builds than the general public. However, to ensure I can discuss features and bugs as beta testers see them, I have both the beta and the most recent build (give or take a week) installed. To differentiate between the builds I wanted to rename what is presented in the boot screen. Since Vista, boot.ini is no longer an option, so here is how to accomplish the rename:

From an administrative command prompt, type bcdedit. This will list all the installed operating systems known by the boot manager. To change one of the attributes (such as the description), you need to know the identifier. Copy the identifier value (from the output of bcdedit.exe) for the OS you want to change the description for, then:

bcdedit /set ID_YOU_COPPIED description “Win7 Rocks”

If you want to change which OS is started by default:

bcdedit /default ID_YOU_COPPIED