Sprint PCS users might want to get the new updated PRL, (roam list), 10013 which is set to be released this week. Sometimes this can be done by calling customer care and they can send it over the air but this method doesn't always work. It's best to take the phone into a Sprint store that has the equipment to do it. Some of the stores are no longer able to. Anyone who still has a PRL of 10010 or lower should really look to have it updated as their are bugs.
Yes you can check on every phone. Problem is each brand/phone has their own way of checking. Some are easier to find than others. Which model do you have?