There are currently (April 08) 4 levels of enhanced listings available to businesses at YellowPages.com:

Bronze Level:

• email link
• link to website
• link to a page with “More Info”, such as payment methods, operating hours and products and services
• line of promotional text not available in free listings

Silver Level:

• everything in the Bronze level
• plus a graphic logo

Gold Level:

• everything in the Silver Level
• plus a banner graphic instead of smaller logo graphic

Platinum Level:

• everything in the gold level
• plus a line of 50 characters where you can place a slogan

Ratings and reviews are displayed for all levels. Advertisers also get pay per call services and may opt into audio ads, gift certificates and online shopping.  The placement of ads within each level is based on a YellowPages.com algorithm that takes seniority, alphabetization and amount paid or willing to be paid into consideration.