In order to use the TestGrid you will need a certifcate to get access to the TestGrid. For this purpose, you can insert your data here and a test certifacte is created for you. This certificate is also directly added to the Unicore User Database at TestGrid and it is included within the downloaded Unicore 6 Bundle.
All you have to do to test Unicore 6 is to enter your name here and download the client. Then you will have a client including a keystore, which grants you access to the TestGrid.