Well my first fishless cycle is finally compelete and now that I've been through one successfully, I thought I'd share my experiences...
I used the Safeway brand of ammonia. It just says "ammonia all purpose cleaner" on the side of the bottle. The listed ingredients are: water and ammmonium hydroxide. I phoned the number on the bottle and the rep told me that the concentration was 2%-3%.
If you decide to use the same brand of ammonia, while you're at the Safeway stop off at the pharmacy and pick up two oral syringes. At my Safeway they give them away for free so just ask the pharmacist. Use one syringe just for adding ammonia and the other for drawing out the 5ml of water needed to perform the tests (I used the Aquarium Pharmaceuticals Freshwater Master Test Kit and the same brand for the Nitrate tests). Using the syringes makes testing a breeze because you always get the right amount and when adding ammonia, you know exactly how much you've added.
Other than that have patience! It took my tank just about 5 weeks to cycle but it finally did. Just add the ammonia until you reach ~5ppm then don't do any tests for at least a week. Testing the water every day just makes the whole process seem longer -- especially when you keep getting this: ammoina: 5ppm Nitrites: 0ppm over and over again -- yes I tested everyday I couldn't help it and it drove me crazy!
www.dejanews.com has a lot of interesting articles about fishless cycling so check that out too.
Its funny because one petstore employee told me that fishless cycling was really complicated and easy to screw up! From my experience this couldn't be further from the truth.
Hope this helps!