After upgrading to Firefox 3, being waiting for the Paste and Go 2 to update it’s installation files to support the final version, no luck. Decided to hack and get it installed myself. Below is how to do it.
1. Download the xpi installation file from the official web site.
2. Unzip using 7-Zip
3. Use notepad and edit the file install.rdf
4. Change following text from <em:maxVersion>3.0a1</em:maxVersion> to <em:maxVersion>3.0</em:maxVersion>
5. Now copy the updated install.rdf files back to the xpi file. You can use drag and drop. i.e. Open the xpi file in 7-Zip then drag and drop the file.
6. In FF3 click File->Open File… then select the Paste and Go 2 xpi file.
P/S: If you had Paste and Go 2 previously installed, make sure you uninstall before you proceed with the installation.