Just a quick note since I'd had several requests for this of late - The Bulk User Delete tool for Connection 7.x was updated today:
this version supports the option of "resetting" a user in place instead of deleting them. There are a number of customizable options for what's meant by "reset" (i.e. empty the mailbox, delete the voice name, reset the passwords, remove private lists etc...). This works with both CoRes and stand alone installs (as opposed to deletes which only work with stand alone installs) - a number of schools in particular were wanting the reset option for coRes installs.
As ever let me know if you run into trouble with it or have suggestions for further enhancements.