Spotting is very common for pill users, especially during the first few months. It often stops on its own when your body gets used to the hormones. Let your doctor know about it when you see him or her though since it can be a sign that you need a higher dose. In the meantime, you can be sexually active, but you might want to use a condom or spermicide just in case your pill is a bit too weak for you.

For more information:

"Spotting: Reassure the patient that spotting is common during the first three months of pill use. Rule out pregnancy, pelvic inflammatory disease (PID), and other gynecologic problems. Spotting may be managed by reassuring the patient, increasing the progestin dose, or increasing the estrogen dose. Initially, try to manage spotting or breakthrough bleeding by increasing the progestin in the pill provided to a woman."
http://www.ncbi.nlm.nih.gov/books/bv.fcgi? rid=cm.chapter.5084

"Birth control pill users, especially new users, often experience spotting halfway through their cycle. Increasing the strength of your oral contraceptives can stop this from happening. Additionally, spotting may be a sign that your pills are not as effective as they should be, therefore you should use an additional method of birth control when you have spotting."
http://www.epigee.org/guide/medfaq.html#ir regular

Unfortunately, it is very common to spot during your first few months on hormonal birth control. I, personally, spotted for the first six months. (i didn't have the option of going on anything different or stronger) But every woman is different. The rule of thumb is, give it three months. If you are still spotting or unhappy with your birth control, contact your prescribing physician. (if you call before the three months, they normally tell you to give it time.) The only time you should not wait is if the interactions you are having are troublesome. There are other options besides the pill that your dr may talk to you about. Good luck!