Delete iTunes account

I would like to delete my iTunes account

You really don't want to since doing so would prevent you from ever being able to reauthorize your system, should that ever be necessary, or authorize a new one.

and credit the $0.74 left on the account (from a gift card) to my credit card.

Sorry but you can't.

I would like to remove all my credit card information from my account

Sign into your iTunes Store account, click on the Edit Payment Information button, and enter in all zeros in place of your credit card number.

Here's what the iTunes Store has said about cancelling an account (paraphrased from an email to another poster):

There are a couple of options that will allow you to retain full access to your purchases while preventing your account from being used to make additional purchases:

1) You can remove your billing information from your account at any time so that it can't be used to make purchases. By doing this, you retain the ability to authorize computers to play the items you have purchased with the account, and you will still have the account open in case you decide to use it later. To remove the billing information while keeping the account open, go to the Store menu in iTunes and choose View My Account. Log in, go to Payment Information, and in the credit card area choose the "none" option.

2) Apple can disable your account, which will prevent it from being used to make purchases, but you will still be able to play the items you purchased with the account. You can also remove your billing information from the account if you wish.

It is also possible to cancel the account, but you may lose the ability to play the items you've already purchased from the iTunes Store. For example, if your computer is repaired, you may not be able to reauthorize the computer to play your purchases after the repair. Also, you wouldn't be able to authorize computers that were not already authorized before you canceled the account. You may sign up for a new account in the future, but your new account will not play any of the songs or videos purchased with the canceled account (and you can't reactivate the canceled account). You should not cancel the account if you want to be sure you can continue to use your iTunes Store purchases. I therefor strongly recommend either removing your billing information or disabling the account as described above.

If you would like Apple to disable (or cancel) the account, you'll want to send a message to the iTunes Music Store through the form at the bottom of this web page specifying if you would like it disabled (or canceled). They should then respond with additional information (some of which I've given above).