Here's a great website with information on different medications during pregnancy. I would suggest bookmarking it (add it to your favorites) so you can reference it easily in case you have any questions.
<A HREF="http://www.perinatology.com/exposures/druglist2.htm#Ibuprofen">Medications in Pregnancy and Breastfeeding</A>
Just be careful early in pregnancy. Medications can be harmful, but so can a fever - even a low grade temp. The most important thing to remember with medications is to weigh the risks against the benefits. If you have a 103 degree fever of course you'd need the tylenol to bring the fever down since the fever could harm the baby. Once you're farther along and everything is formed, you're generally ok with most meds.
Here's something from a booklet compiled by the National Naval Medical Center in Bethesda, MD (where the President of the US goes).
A mother should be especially cautious in the first trimester
Street drugs are definitely out
No one, especially a pregnant woman, should take medication prescribed for another person
Most drugs should be taken under the doctor's orders
Over the counter medications that are allowed are:
Tylenol (acetominophen) can be taken for headaches and minor pain relief
Antacids (Mylanta, Tums, Rolaids) may be taken for heartburn and gas
Sudafed (pseudophedrine) for nasal congestion
Robitussin for coughs
Sucrets or Cepacol throat lozenges
Metamucil and Surfak for constipation
WHAT CAN I DO IF I HAVE A COLD?
In general, over the counter cold remedies may alleviate the symptoms but they do not alter the course of your cold. We genreally recommend that you try to remain comfortable, force fluids, use Tylenol to keep temperature down, and if need be, you may rarely use Sudafed, as directed, to control congestion. Although none of the commonly used cold remedies are approved for use in pregnancy, there is a fairly large experience with Sudafed and it appears to be safe. You should take no medication chronically during pregnancy. Saline nosedrops may also help provide you relief. If yo take cough medicine, you should only take those that do not contain potassium iodide. Again, there is a fairly significant experience with drugs such as Robitussin and Cepacol and they do not appear to cause an increased risk to your pregnancy. One final point in regards to cough medicine is that you should avoid those that contain alcohol. Some of these medications contain as much as 25% alcohol by volume. There have even been children reported to have developed fetal alcohol syndrome secondary to cough syrup abuse.