1. click on Manage Devices
2. click on the settings button for your Library (little black sprocket looking icon, next to the green online icon)
3. click on the "Bulk Label" ("Media Label" in 10.0.1) button at the bottom of page, and you'll get a drop down window
4. where it says "Group Label" enter a group name (ex: Daily Exchange)
5. if you want all media labeled the same, click on the "All Media in List", if you only want a few just click on One first, then "CTRL+Click" on the other ones, which will highlight each one you want.
6. once you've finished choosing, type LABEL, in the window that says "Enter Label to confirm request"
7. click OK
This will label your tapes, if you want to label another set of tapes with a different Label, just repeat the process above.