Information technology is covered in several resources including:

• MarketResearch.com Academic - Mind Commerce Publishing reports covers the IT sector 
• Mintel - Category - Technology & Media - Technology
• Statista - provides access to charts, graphs, and other statistics
• Passport (Consumer Industries) - search for technology

Visit the iab (Interactive Advertising Bureau) and search for technology.
See also the IAB Advertising Spend and Revenue Research.

Visit:

• ClickZ
• E-Commerce Statistics (E-STATS) from the U.S. Census Bureau
• Digital Commerce 360