The web site says they now support iPhoto 4 to 7; the version commitment is a much requested improvement. iPhoto 7 comes with iLife '08, the blog posting here calls it iPhoto '08 (emphases mine):
Today's release of version 1.1 of the Picasa Web Albums Uploaders adds support for Apple's new iPhoto '08... this release installs and updates via Google Updater to ensure that you are running the latest version.The last bit almost sounds like an apology. The language of the post is a bit ambiguous, but it sounds like they've updated both the standalone OS X and the iPhoto plug-in uploaders. The Keyword to Tag conversion is much appreciated.
While our first release used a private API to talk with the Picasa Web Albums server, the new version is built on the public Google Data API interfaces and our Objective-C GData Library. This will make it easier for us to keep up with Picasa Web Albums' new features. For example, the iPhoto export plug-in now can convert keywords in iPhoto to tags in Picasa Web Albums.
Our goal is to keep the Uploaders as quick, straightforward utilities that make Picasa Web Albums readily available to Mac users. You can give us feedback about them at the Picasa Help discussion group.
Update 10/27/07: Unfortunately, there's a significant regression in the new uploader. The old uploader concatenated the iPhoto Name and Description fields. The new uploader maps the Name to PWA caption and ignores Description. This behavior should be configurable, but, more importantly, Google needs to open source the uploader so users can configure it.
Update 10/27/07b: Someone who seems pretty knowledgeable responded to my Google Groups post. Their was real thought put into the design, though I fear the thought was misguided. It actually uses the Name field value if it's been changed, otherwise it uses the Description field value. So the behavior is going to seem unpredictable to many users. The author clearly is not an iPhoto expert, or he'd have known that Batch Update makes it trivially easy to set the Name value to a date or meaningful string with counter; so that edits to comments are an easy extension. This needs to be fixed.