Sharing icons by email and Dropbox never really captures the way each image will appear on-screen. That's why developer Michael Burford and his brother created a web page mock-up solution that automatically adds an iPhone background and styles the icons to match the way they display on-device.
He built a PHP/CSS toolset that you can place on a web host to serve icon previews. The script detects your browsing platform, so the previews look right on both iPhones and iPads.
You can download the tools from his web page. Make sure to stop by and read his full write-up for details about installing and using these.
