The OP is talking about a "secured" credit card.
Typically you put up an amount of money into an interest bearing savings account. Then the credit card company gives you a credit limit equal to the amount of your deposit (some give 150 or 200% of your deposit amount).
Most companies charge an initial fee for this type of card. In addition, they may charge you a monthly fee.
The companies that carry this type of card that are reputable are: Providian, Bank One, and Capital One.
I know several people who prefer the secured cards over unsecured cards. For the "overspenders" of the world, this is great because you dictate your credit limit. It is also a great starter card for a college freshman.
Yes, the interest rates are much higher on these cards, but remember to subtract the amount of interest you are receiving on the savings account to get the true APR. These types of savings accounts typically pay a higher interest rate than a typical savings account.
Lastly, these secured cards do help your credit rating. And with good payment history, the credit card companies may give you a higher credit limit (that is unsecured). Additionally, some send you back your security deposit after a specified time of good payment history.
HTH.