A pap smear is a yearly test all sexually active women need to get. It tests for abnormal cells on the cervix. It does not test for stds unless you request those specific tests.
It generally takes approximately a week or two to get the test results back. You are usually only notified if you do have an abnormal pap, otherwise they don't bother sending a letter.
It is not uncomfortable physically. If you are concerned, take some ibuprofen about 1/2 hour before your appointment.
The doctor will use a speculum (sp?) to hold open the vagina. These tend to be plastic now and not as uncomfortable as the old metal (and always very cold!) kind that sometimes pinched. Then s/he'll look inside and scrape a very long q-tip on your cervix. It can be a little sensitive feeling but it isn't painful. After that, s/he'll take out the speculum and feel inside with one hand and push on your stomach with the other - they are feeling how large your uterus is. They might tell you something like you have a tipped uterus (not uncommon and nothing is wrong with that) or your uterus feels fine. They also feel if your ovaries are enlarged.
Then it is over. Oh, sometimes they do a breast exam also.
It all takes about 10 minutes.