May I ask why you want an H-1B visa for your spouse? If it is simply to work, with L-2 status, he can apply for the employment authorization document (EAD). He does not need the H-1B visa. The EAD will give him the broadest options for employment and he will not have to compete for limited H-1B visas available. It takes about 3 months to obtain an EAD. However, if your husband has not had H-1B status previously, the earliest an employer would be able to file an H-1B petition is April 1, 2009 for an October 1, 2009 start date.
If your husband obtains H-1B status and he loses his employment, he will not automatically revert to L-2 status. He will have to apply for the L-2 either in the U.S. or in India depending upon the circumstances of the H-1B termination. You should contact an immigration attorney immediately to fully address your situation and options.
To answer Q.3, after your husband gets his EAD approved there is no need for him to find a sponsor. As mentioned in the other post, as an L-2 visa holder with an EAD, he will be able to start working immediately with any employer that wishes to hire him.
Additionally, not only will he have to wait until April 1 of next year to file for an H-1B which will only be valid from October 1 of that year, but further, the H-1B visa numbers are so limited that his H-1B petition might not even be processed.
Accordingly, he is in a very good position with an L-2 visa. The only step that needs to be taken is to apply for his EAD and find an employer. No additional petition needs to be prepared.