Akers' agent told Jeff the 5-time Pro Bowl kicker has agreed to a 3-year deal with the 49ers.
Akers, doing some tweeting of his own, wrote, "I'm really excited to be a 49er!!!"
Akers has been an Eagle for 12 seasons, including the 2004 Super Bowl team.
The 49ers can't announce the signing until Friday.
Akers is coming off consecutive Pro Bowl seasons, and showed no signs of slowing down last year - he set a career high with 23 touchbacks. But the Eagles drafted kicker Alex Henery in the fourth round, making Akers expendable.
Philadelphia had placed the transition tag on Akers before the NFL lockout, but that became invalid.
Akers has connected on 81.9 percent of his field goals and 98.7 percent of his extra points. He was cut by three different teams before signing with the Eagles in 1999.
Akers went on to set the franchise record for points, field goals, extra points, games played in the regular season and in the playoffs. He was selected to the NFL's All-Decade team for the 2000s, and only Morten Andersen (seven) and Jan Stenerud (six) have made more Pro Bowls.
Associated Press writer Rob Maadi contributed to this report.