The simple solution is a high yield savings account. Open online at Ally.com or DiscoverBank.com or Capitalone360.com. I believe you can make it a joint account (though CapitalOne360 was a bit clunky for doing that.)

When the account is set up, link your existing checking account to transfer money into the new savings,account (or back out). Transfers take a couple of days but are very straight forward. (They are ACH, similar to direct deposit or online bill pay.) These are paying a little over 3% currently.