It is really simple actually. Right-click in any credit list in Album properties dialog box. You should see a new menu with commands:

Copy Rows
Paste Rows
Cut Rows
---
Delete All Rows

If you don't see it, try clicking on column headers or below the text area (as opposed on actual credit items).

"Copy Rows" will put all credits in current list to clipboard. "Paste Rows" will do the opposite. Note that you can use this feature not only with OrangeCD, but with Notepad or other apps as well.

I hope this helps.

Andrei