will a cash-in refi make my term shorter?

There is no need to refi, unless your rate is higher than 5% or 5.5%. Just pay larger monthly or lump sum payments, and your loan will pay off faster.If you do refi, in order to get a lower rate, the same rule applies. A 15-year term loan will have a lower interest rate than a 30-year term loan.

A Cash-In refinance means that you BRING money to the table to pay down your existing loan to a Loan-to-Value level that works with your loan program. You would refinance, but bring the cash to close necessary. Typically, getting the LTV to 95% or less. If you are underwater and your last mortgage closed prior to 6/1/2009 there is a chance you can qualify for a HARP refinance. which does not require any principal pay-down. It's pretty much just a refinance where you lower your interest rate, term, or payment. Have you checked to see if you are eligible for HARP?

Making extra monthly payments will reduce your principle therefore allowing you to pay your loan off sooner. However, a "cash-in" refinance will reduce your principle, not necessarily shorten your term. Rather than doing that I would recommend you refinance to a shorter term and possibly use the cash to reduce your rate. Feel free to contact me if you would like to discuss your options.

It really depends what you are trying to accomplish. The mortgage term is what you agree to, and whether you make additional principal payments during the life of the loan which shorten the term. Any payment you make pays the loan down faster, even adding an extra $25/mo makes a significant difference over the life of the loan - and sometimes that makes more sense than refinancing. You need to discuss your situation with an experienced and reputable mortgage officer who will help you evaluate your options.