Beal, a British and Irish Lion in 1997, who won the last of his 15 England caps in 1999, will remain with the Saints squad for another season, taking them through the World Cup period and to the end of 2003/04.
The 32-year-old is one of the most experienced players in the playing squad, with 234 appearances under his belt since his arrival in the 1991/92 season. He is the current highest try-scorer in the squad with 66, as well as 21 conversions, 21 penalties and two drop-goals to amass a Saints' career points tally of 364 to date.
Northampton Saints Operations Director John Steele said: "Nick has been back to his best this season and he has agreed to play a further year for the club. I think he is enjoying his rugby and we are certainly enjoying his current form."
Also signed up for next season, on a two-year contract, is Fox, who made the biggest impression on his Saints' career so far during the Powergen Cup semi-finals when he scored his first try for the club.
Now in his last year as an Academy apprentice, the 22-year-old has signed a full professional contract to mark a positive conclusion to nearly two seasons of serious knee injuries that involved two operations.
Said Steele: "We are delighted to have signed Darren on a two-year contract. He has been particularly unlucky with injuries but has shown tremendous determination and courage during his rehabilitation and is now repaying the faith the club has shown in him. His recent performances have indicated that he will be a top player in the future."
Both Beal and Fox will feature in the starting line-up in Saturday's Zurich Premiership meeting with Bath at The Rec. Kick-off is at 14.15 GMT.