Athlete's foot, as you probably know by now, is a fungal infection of the skin of the feet. It causes symptoms just like those you are describing - redness, itching, and cracking and dryness of the skin of the feet.
Treating athlete's foot begins with good hygiene, since the fungus is spread through contact with contaminated clothing and the like. Washing your hands frequently, avoiding scratching, and changing and laundering your socks regularly are all very important.
In addition, most simple cases of athlete's foot can be managed with over the counter anti fungal creams or sprays (such as those you have seen advertisements for on TV). More severe cases may require prescription medications from your doctor
I would recommend that you go to see your primary care doctor
about this issue. They can examine your feet and confirm that this is indeed athlete's foot (as opposed to another skin condition potentially requiring a different type of treatment completely). If athlete's foot is confirmed, then they can also give you advice about which medication you should try to clear up the infection, whether that be an over the counter or a prescription medication.
Good luck, and feel better soon!