Banks are always changing their interest rates depending on what's going on in the financial markets. For example, I have an account with ING Direct (an online bank) and they have dropped their interest rate at least 5 times in the last several months. Over the last few years my rate has gone up because the economy was better, so the changes can go either up or down. With a savings account, you don't have to open a new account to get the new interest rate.
No joke, it's actually kind of been funny...
Mar 19, 2008 Interest Rate Change to 2.960% (3.00% APY)
Mar 11, 2008 Interest Rate Change to 3.057% (3.10% APY)
Feb 1, 2008 Interest Rate Change to 3.348% (3.40% APY)
Jan 23, 2008 Interest Rate Change to 3.590% (3.65% APY)
Best rates right now are Alliant CU savings at 4.35 or there are several rewards checking that gives 6% (but you have to use debit card certain amount of times each month, have direct deposit, etc).
As far as rates go, most banks will change your interest rate with the fed rate, up or down. If not, it gives you a good excuse to switch to a different bank with a better rate.
And there is no difference between a savings account and a money market
deposit account other than whatever rules that bank makes up (usually savings accounts have lower minimum balance requirements), they are both FDIC insured. A money market
fund account is not insured.