Apple has release a beta of Safari 4 on Mac and Windows. It looks to be extremely fast. It looks like this new version might break many (all?) Input Manager "plug-ins"/hacks, so be careful.
And here's a link to the nightly WebKit downloads for anyone wanting to use the absolute latest greatest, without having Safari 4 overwrite Safari 3. With a recent Webkit installed, you can run both versions.
Update 1: After briefly testing, I was surprised to find the nightly builds of WebKit are still based on the Safari 3.2.1 . The Safari 4 installation overwrites Safari 3.x, so I'll try it and check if the WebKit builds still use the older version (which is compatible with most modern Input Manager hacks). Or I may be reduced to using Multi-Safari, which should allow you to run a self-contained, older version of Safari/WebKit, without disturbing the primary Safari installation.
In a pinch, if you have problems with Safari 4, you can download Safari 3 again.
Update 2: And it looks like it may be possible to make some Input Managers function. At least I found some instructions which might work for 1Password (a nice password management and archiving utility with an optional iPhone app with wifi sync'ing).
Update 3: You can enable 1Password to function with Safari 4 as mentioned above. Here are specific instructions for the Safari 4 Beta release. And you can re-enable the 1Password toolbar icon by editing your toolbar with View --> Customize Toolbar.
