This post comes a little bit late but since 12/26/2008 there's a new version of the "still indispensable" Photoshop Plug-In from Canon,
Easy PhotoPrint Pro.
It's version 1.6 and can be downloaded for free
here. Just select the OS on the dropdown and second in the "software" section you'll find it.
It now supports Adobe Photoshop CS4 (32bit / 64bit versions).
I still cannot match the quality (specifically color gamut) that I get printing from PhotoPrint Pro to my Canon PIXMA Pro 9000 to that of printing directly from Lightroom. I suspect that it is because PP Pro can output in AdobeRGB as opposed to sRGB which is what I suspect Lightroom is doing. Given that The PIXMA can print in AdobeRGB it's a crime IMHO not to take advantage of that but I cannot actually determine by searches I've done, WHICH is the colorspace Lightroom outputs to the printer. I guess I'll research a little more and post what I find here.
My workflow right now for printing is opening the photo in Photoshop from Lightroom like if I was to edit it (which creates a copy of the file in disk) and then open up PhotoPrint Pro to print from there. Once I'm done, close out of PP Pro and Photoshop and delete the duplicate photo file (if I didn't edit it in PS). As you can see this is a pain, but it's the only thing that works the best for me.