Having turned down a new deal with Stanley, striker Grant has agreed a move to Scunthorpe United, who will pay compensation to the Lancashire club.
"I think both clubs are reasonably happy with the figure that's been agreed," Scunthorpe general manager David Beeby told his club's official website.
A similar deal is in place to take midfielder Donnelly from Aldershot to Swansea City.
He told Swansea's official website: "I had a few offers on the table, but as soon as Swansea came calling I didn't have to think twice about it.
"Swansea are a top Championship club with a top manager. And, from what I've seen, they play some of the best football outside the Premier League."
Also wanted in the Championship is Gillingham hotshot Simeon Jackson, the subject of a £500,000 bid from Norwich City.