LastPass for Safari is now available, it has the ability to import your saved passwords from Safari built in and importing 1Password entries is easy too (LastPass Icon -> Tools -> Import) . The combination of a compiled LastPass addon plus Safari's speed means that Safari 4 + LastPass is also the fastest combination on OS X!
To get it simply fire up Safari and go to https://lastpass.com/ and hit 'Get LastPass'; if you're new to LastPass you'll also need to create an account. You'll then need to fully restart your browser (Safari Menu Item -> Quit).
We've worked hard to try to add all the features available on our other platforms, and we're largely there. There are also a few unique to LastPass Safari features like if you customize the toolbar you'll see 2 other possible buttons: Fill and Submit and Form Fill for easier access to those capabilities. We still have a few notification preferences to add, and potentially a local vault and multi-factor authentication is currently disabled.
It does work with Snow Leopard (OS X 10.6) but you must set Safari to run in 32 bit mode (Go to Finder -> Applications -> Right click on Safari and hit 'Get More Info' then set 32 bit).
LastPass for iPhone has benefited from this effort, and we're sending a new build to Apple's App Store queue tonight which has added Form Fill, Identity support, Offline network retries, local file writing, a password generator and more. Our commitment to OS X will also have us syncing your Keychain data soon too.
And before you ask, we've stared on Google Chrome and Palm Pre; they're next on the docket and will be completed soon.