I am, according to 1Password, running the latest beta.
I am running the most up to date Lion.
I can install the extension and the 1P button shows up.
I can click the button, and some unfamiliar "unlock" window comes up.
When I right-click on a form entry, I do not see the 1Password additions to the menu.
Alternately, if I open/unlock the 1Password app, and go to a password entry, and click on the item which usually takes me to that page and fills in the fields, it goes there, but does not fill in.