I haven't seen this anywhere yet, but I just got an email. If you check the FastClick site, choose publishers, then ad formats, you can see what they look like. They also offer this info:
Publishers may display Text Ads with customized dimensions and colors to help integrate the ads with site their design.
Text Ads are made up of four pieces:
Headline: 25 characters maximum
Description Lines: Two lines; 35 characters maximum per line
Display URL: 35 characters maximum
Destination URL (hidden): 255 characters
Publishers can choose to display a maximum of seven Text Ads
Customizable shapes and sizes
Text Ads can be stand-alone or bordered
Background color can be set to match the color of your site
No word if they'll be CPM or CPC yet, though.
Anyone else hear anything?