Dear Sir/Madam
I am writing this letter to inquire about the availability of postdoctoral positions in your laboratory. I have been recommended by my thesis advisor (name), who suggested me to write to you, since you are initiating a research program in (topic of research). I am keen to participate in this research.
I am enclosing my resume for your review, which will show you the range of research activities that I have been involved in. I believe the postdoctoral position in your lab will provide me with the support and challenge for which I am looking.
I am further enclosing letters of recommendation, (including---). I am looking forward to hearing from you.
Sincerely,