Dear [Prof of Interest[ ,
I'm applying to the PhD program in neuroscience at [University] for fall 2010, and I'm especially interested in your lab. My previous research experience is in [research area], but I am also interested in [neuroendocrinology].
I would like to learn more about your work, particularly your recent paper on [subject of the paper]. My experience working with [developmental stuff] taught me [something relevant to endocrinology], so I am especially intrigued by the connections between the endocrine system and neural development. Is this something that I could explore in a rotation with your lab? Are you currently accepting new graduate students?
If you have the time, I would love to discuss this with you by email or by phone (you can reach me at [number]). I am also happy to tell you more about myself and my background, and can provide copies of my CV and transcripts upon request.
Thanks for your time, and I hope to hear from you soon!