Despite the "WordPress 2.5+ ONLY" disclaimer, this plugin does work with WordPress 3.0x, however, the custom logo option doesn't seem to work. And even though logo uploading appears to work (verified via FTP - "/wp-content/uploads/"), the registration page continues to show the old WP Logo... but with space reserved big enough to fit the logo you uploaded (and there is no "Organize my uploads into month- and year-based folders" option to "uncheck" in WP3).
Also, the "Password strength meter" does not change from "too short" no matter how many characters you type. Be sure to leave this option disabled.
For the logo, a simple fix would be to allow the user to enter a URL for the logo they wish to use.