Let us say that you signed up for a business internet connection last month and paid the first month's subscription by credit card. One way of entering each month's transaction is to wait for the bill to arrive, make the payment, and then enter into GnuCash by hand. However, there is a better way. This will not only save you a lot of time but GnuCash will also pop up a timely reminder, in case there are penalties for late payment.
Open the Expenses:Internet account register and create the $99.50 payment for the first month manually. Use Liabilities:Credit Card as the Transfer account. Use a date of a month ago plus a couple of days. For example, if today's date is 07/19/10, use 06/17/10 as the transaction date. (Why? This is because, we don't want to wait for another month to see how GnuCash reminds us for the second month's payment.)
Once the preceding transaction has been created and saved, right click on that transaction...