Now that you've smelled God, I would like to recommend NeilMed Sinus Rinse. If you are a singer, or an allergy sufferer, this is a must-have. Sure, it is gross, slimy, and unpleasant to squirt saline water into your nose, but it really works well. You see, despite having a humidifier, it gets REALLY dry in my room. My sinuses get too dried out, and I'll spare you all the details, but irrigating my sinuses keeps my nasal passages moist and clean. What this means is that I will have fewer sinus infections, no more post nasal drip, and my voice will be in better form to sing because I won't be as dried out. Read the reviews here: http://www.achooallergy.com/reviews-all.asp?pid=1166
You can purchase this product at any drugstore: Walgreens, CVS, Rite Aid, Duane Reade, etc.
I also recommend purchasing a humidifier while you're there as well.
So, I figured I would post some helpful information for you singers out there who suffer from nasal drainage problems. If you know of any other remedies, please post them in comments.