I've just uploaded version of my Lightroom plug-in Search & replace, Append, Transfer which includes some big changes:

  1. It should work in the LR3 beta (but remember, the beta is not meant for real work)
  2. Instead of the long drop down lists for choosing fields, there are now dialog boxes
  3. The new menu item “Library>Plug-in extras>Parse and audit” reviews your metadata entry
  4. 16 custom fields, plus fields for Event and People like in iView/Expression Media
  5. An optional module converts certain iView/Expression Media metadata fields to LR
  6. Documentation is both beefier and prettier

Parse and audit runs through your pictures, checking whether you've completed the title, caption, how many keywords each image has.