Before your owners leave -- or before you move on to the serious partying -- make sure everyone is clear about the players they've drafted and the makeup of the other teams. If players have been traded, the team they ended up on should also be clear.
You'll want to make up a waiver list of the remaining available NFL players. Make sure everyone understands the deadline for filing each week's roster. If you've made up copies of the rule book, distribute them now. Make sure all fees have been paid. Some leagues appoint one owner as treasurer to handle the cash.
Set dates and announce plans for future gatherings. Some leagues get together regularly. Others only meet again at the end of the season. Make sure you have contact information for everyone. And as soon as you can after the draft, enter team information into the web site you're using.