What's the best way to sync Chrome bookmarks to iPhone?

Just download the free (!) Google Chrome app on your iPhone and then you can simply share and sync all your desktop bookmarks to your iPhone/iPad.

You could give Xmarks a try. Works fine for me.

You install it as a plugin for Chrome, and as a pref pane for your Mac. Your Mac will be synchronized to your iPhone.

I didn't try the mobile app yet.

Since I don't have the reputation to comment, I have to put this in an answer.

I can second the XMarks service as a great way to sync bookmarks between browsers, especially Internet Explorer (IE) and Safari, and especially if you want to sync your iPhone bookmarks with Firefox. There are problems with duplicates from time to time, but that is mitigated with a Duplicate Detector plugin for Firefox.

However, the XMarks service will be shutting down as of January 2011. There is information in this blog post as to how it might live on. http://blog.xmarks.com/?p=1945