I had been working in L1B visa for the past few years.I have an employer who wants to file for H1B for the year 2009.Just in case if my H1B approval is received in a few weeks, can I start working for my H1B employer right away with just the approval pending/ papers without travelling to my home country to get the H1B Visa stamped.

If the change of status (COS) to H-1B is approved, you can begin working as an H-1B. You will not need to get the H visa unless you need to travel internationally and return to the US.

This question really should go to your HR, then to the immigration attorney for the company. They are the ones that know if a COS or consular notification was requested on the I-129.