Be very careful.  "Reviewing and stamping" plans or drawings which you were not involved with creating is called plan-stamping and is illegal in all states that I am aware of.  Almost every newsletter from the state has a legal case against someone who has done that.  Punishment ranges from fines of several thousand dollars to loss of license.

If you really do a complete review, including of calculations and all the numbers, I don't see how that is illegal?

This is no different than at most EPC's, where there may only be a single engineer with a stampe for a particular state that they are doing work in, but the home office is in a different state half way across the country.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

Agree with the essence of what jpankask says.  A complete review with calcs per Ashereng is also done, but you need to be able to get into and design all essential parts of the design.

Also, in many states, a PE seal/involvement is not required for residential homes below a certain size.

Insurance (your original question) - not sure there - perhaps your contract could include a limit of liability clause and then you could go talk to an insurance carrier to see what they offer and how much it will cost.

It may not be the same in all states, but the states (in the Midwest) where I am familiar with the rules and statutes specify that for a PE to seal a plan or drawing, they MUST be involved with the design from the start and oversee the creation of the drawings and plans.  That is not to say that they have to do all of the work but they must have "responsible charge" of the work and oversee the person who does the work.  Simply reviewing plans and stamping them is not responsible charge, even if you recreate every single calculation.  Now, that said, it happens every day in every one of those states and some people never get caught.  But if someone finds out and turns you in to the board, you risk losing your license.

JAE's comment that a PE seal is not required for residential homes is also valid in these Midwest states.  Single family dwellings, whatever size are exempt from PE requirements.  

The moral of the story is to check your state laws and be sure you understand all that is required before you proceed.

sjhgeotech:  

Liability insurance is expensive and can have limitations.  People who ask you to seal (not design from beginning to end) drawings often have a reason for not getting you involved completely.  When you seal (sign) you assume responsibility for ALL the work in your area of licensure/expertise.  I would suggest you run the other way or, as a bare minimum, insist on going back to the very beginning and redo everything.  Get a contract in writing from this guy.  With all do resepct to honest contractors, my experience is that contractors will try to cut corners wherever/whenever they think possible.

Remember the Kansas City Hotel Walkway collapse.

Regards
Dave