As we emphasize in all our information on jumbo loans, jumbos are not that different from regular loans. Thus, the best place to start searching for a jumbo loan is at your local bank or wherever you feel comfortable getting a regular loan.
On the other hand, jumbo loans are a somewhat rare commodity, so large banks and brokerage firms will usually have more experience dealing with them than will small, hometown banks. You might also check the Internet; you can apply for a jumbo mortgage online and get competitive offers from multiple lenders. As with any Internet product, however, you'll want to make sure you're getting a legitimate offer.
As you talk to potential lenders, don't be afraid to play dumb and ask lots of questions. Make sure you get clear figures regarding what your payments will be, when your loan is paid off, etc. Ask about the different types of loan you can have and the advantages and disadvantages of each. Do you want a fixed or adjustable interest rate? Should you get a ten or thirty year loan? Will you be able to refinance later if your principal debt falls under the jumbo loan floor? The more questions you ask at the front end, the less likely you will have a surprise you don't want later.