I have a couple Capital One Online Money Market Accounts. These accounts are only available online and you CAN NOT make deposits in a branch. You can only make deposits through the mail or through online transfers. If you have other Capital One accounts, transfers take place instantly and there are no holds on funds. However, if you don't have other Capital One accounts, transfers can take a few days to post and they place a hold on the funds.
In order to open up an account, you have to visit Capital One's website and follow the directions. It is very simple but they will go through a verification process. Once you complete the account opening, they will send you the paperwork in the mail to complete.
There is no minimum balance and no fees associated with this accounts. It is currently paying an APY (annual percentage yield) of 5.0%. That is an excellent rate since there is no minimum balance required.
For me, these accounts are simple to use because I have other Capital One accounts. I simply log into online banking and transfer the money back and forth. However, I do have one non-capital one account linked to it and transfers from that account take 3 days to post and then there is a few day hold on it. If you are not going to be in immediate need of your cash, this is a great account because of the high yield.