From the Nokia Beta Labs post:
The Store QML client for Symbian is available for Symbian^3, Anna, and Belle phones. This release (3.30.005) includes:
- added additional billing support.
- error fixes, e.g. the client crashes when the user presses the search button during the start-up.
The Store client for S60 is available for S60 3.1, S60 3.2, and S60 5th Edition phones. This release (1.30.004) includes:
- improved user experience by allowing longer product description
- added additional payment methods
- error fixes
Note that in each case you'll need to sign into Beta Labs with your usual Nokia account. On each of the download pages is a link to give feedback to the Beta Labs team, in case you hit problems.
Here are screens from the install of the S60 5th Edition version (confirmed also working on older devices such as the Nokia E71 and E72):