In Squeak 5.2, you can install the tools through SqueakMap. They are listed as "Refactoring Tools".
Have a look at Refactoring Browser, however the refactoring tools can be used with the standard Squeak browser now, when you install them.
Note for users of older Squeak releases:
The OmniBrowser is not usable in Squeak anymore and also not being developed either.
Since the refactoring tools are available for the standard browser now, OmniBrowser is not needed.
