If manufacturers combine the motherboard CPU and the PC motherboard, this can save you money. Most customers like the motherboard-CPU combo because it saves them money and time. Don't overlook sales on dual-core processor motherboards (computer motherboards industrial strength). Sometimes these can be a steal, especially since companies are always looking for faster processing speeds.
Look at individual motherboard manufacturers' websites for their PC motherboards. To become more familiar with motherboard manufacturers, look at AnandTech's website. AnandTech covers every motherboard you can think of. Find additional motherboard information at Tom's Hardware. They will have photos of the motherboard, and go into depth on each feature. They also will give you the pros and cons of motherboard bundles, such as: Is it smart to have audio and video integrated on the motherboard or is it better to purchase these items separately?