There is a hefty patch porting the MenuTrails module to Drupal 7, but it is reported to not work (read: cause fatal errors with) Organic Groups.

See also: http://data.agaric.com/breadcrumb-control

Here is how i customized the breadcrumbs for galleries to remove the username, building on the documentation at http://drupal.org/node/544748#breadcrumbs and contributing back to that page what you see below:

Agaric would like breadcrumbs in Drupal to just work, but barring that until book navigation becomes general navigation in Drupal 6, we'd just like control...

Custom Breadcrumbs module
http://drupal.org/project/custom_breadcrumbs

From the PHP snippet section...

Breadcrumbs including title

http://drupal.org/node/64067