Pregnancy and your feet
Pregnancy will almost always be associated with swelling feet and ankles. For more information on this condition, see
edema. As you get further into your pregnancy you will need to sit down more and take longer rests with your feet elevated to reduce the swelling and soreness. As you get to the final stages of pregnancy, you should stay off your feet more than usual. It is encouraged to take short walks and get frequent exercise, but balance it out with lots of R&R (you'll be happy you did.) As for the soreness and swelling, it is caused by edema, but since it's pregnancy related you should make sure your doctor or child birth education classes don't have anything better.
For when the times get rough
When you are forced on your feet for an extended period of time and they are just killing you, relax! You need to find a place to lay down and put a couple pillows under your feet. You need to get your blood to circulate through your feet instead of gather there. With the added weight of pregnancy, your feet will get really sore, so it's best to have a place already set up for you to just lay down and put your feet up. If it still is taking a while and you feel your feet pulsing, try wrapping a bag of ice in a thing bed sheet and put it on top of or under your feet\