I just had a problem with my HTC Diamond today and this is how I handled it. Called Sprint and told them I had a manufactures defect on my phone and they said it will cost money to fix since you dont have insurance, I said its under the manufactures 1 year warranty to which they gave me the number to HTC. So I called HTC and they told me a 2 week turn around for repairs, so I called Sprint back and told them I can not be without my phone for 2 weeks. Sprint put a note on my account and told me to take it to a sprint store, which I did and they fixed it for free.
Or here is a great post to read which is basically what I followed.
http://forum.ppcgeeks.com/showpost.p...59&postcount=5