Check out http://www.protagonize.com, a collaborative creative writing website. All IE CSS3 shadows, gradients, rounded corners, etc. powered by CSS3 PIE.

Cheers,
-nick / protagonize

Hey everyone,
I work for http://dyn.com and we use PIE for our http://dyndns.com Internet Guide landing pages! http://dynguide.com/ has an explanation of what Internet Guide is.

http://setup.dynguide.com/ is our setup/status page, which lets you know if Internet Guide is enabled/setup on your computer (this is where we use PIE!).

If you set your DNS IPs to use the Internet Guide ones and visit a phishing site such as badguy.com (WARNING, this is a REAL phishing site!), you can see our block pages (also using PIE!).

Great work on PIE! We love it!

Uses PIE for multiple background images... which gives it its grungy border effect...

http://www.socialistproductions.org/

And another one of my sites just went live. Using CSS3Pie mostly for border-radius, check it out;
CustomBits.net

p.s.
Just read on the blog you guys will be supporting linear-gradient on IE9, for now I already have an elegant solution posted on my blog (using SVG), find it here.
Might also be interesting for you guys, tweaking fancybox to have rounded borders using css3pie

roomandboard.com is using pie for drop shadows, gradients and rounded borders. It's been a real pleasure to work with.

Just got it working for a client's site: http://aroommatesurvivalguide.com/. So far it's just rounded corners on the main content area, but I'll enable rounded corners elsewhere and then see what other CSS3 effects I can get working.

Had some problems until I finally noticed that the URL to the PIE.php file MUST be an absolute path.

I'm just using div radius but after adding pie, the site look like its suppose to in IE8. Don't have any lower IE browsers. I can't believe how simple it is to install. This is going to reduce editing, and page load time. I had been using radius properties for google chrome and just letting IE be square. Not any more. Great fix!

http://sourfly.us/

http://www.bitcloud.com.au

Mostly round corners and some rgba. PIE made things so much easier. Thankyou!

PIE is used for some rounded corners and so forth on the new Connecticut Health Foundation website: http://www.cthealth.org/
Built by Vermilion: http://vermilion.com/

http://modemerr.com using border-radius and linear-gradient on starburst-esque element over the cover photo.