There are many opportunities to play USCF rated events online. Recently, I have been sharpening up my skills on ICC (Internet Chess Club). The following tournaments on ICC are USCF rated:
1. Monday at 7 PM Server Time, there is a 7 round Swiss with a 3 2 time control.
2. Saturday at 5 PM Server Time, there is a 5 round Swiss with a 12 3 time control.
The ratings from these events are posted in a separate category from over-the-board ratings and are displayed as "online ratings."