First, you need to determine if your client machine that you will be using to connect to Exchange 2007 server is 32-bit or 64-bit.
To download the 32-bit tool, you can go here — http://www.microsoft.com/downloads/details.aspx?FamilyID=6be38633-7248-4532-929b-76e9c677e802&displaylang=en
Then go through the normal install as if you are going to install the Exchange 2007 Server — make sure you choose custom install.
Then, uncheck every option except for Exchange Management Tools. This will install Exchange Management Console and Exchange Management Shell.