Gas, water, telephone, electricity, and NHK (television) bills can be paid automatically from your bank or post office account at no extra cost. To apply, take your bank passbook, hanko (the one you used to open your bank account), and utility bills to the bank. Alternatively the utility companies can send you some forms to fill in and mail back to them.
You can also pay utility bills at convenience stores, and sometimes via a Japanese credit card—handy if you have a card that is associated with an airline and you're trying to accrue frequent flyer miles. You will either need to apply online or have the utility company send you the forms.
Electricity and gas bills are paid every month and water bills are generally paid every two months. NHK bills may be paid on a monthly basis, but you receive a discount if you pay on a half-year or yearly basis.