Wilson, Pittsburgh's starting shortstop since 2001, is the club's longest-tenured position player. He's also the Pirates' highest-paid player at $5.25 million this season and is due to make $6.5 million in 2008 and $7.25 million in 2009.
The Cubs will receive a player to be named.
With the Pirates well on their way to a 15th consecutive losing season, they could be looking to shed Wilson's salary as the July 31 deadline for trading without waivers approaches.
The Pirates already have former starting second baseman Jose Castillo as a backup infielder who plays infrequently, and there would be no reason for them to add Izturis without trading another starting infielder.
The 29-year-old Wilson, a .264 career hitter, has a .254 average with four homers and 26 RBIs this season. On Monday, he became involved in a dugout shouting match with pitching coach Jim Colborn after Wilson failed to catch a popup that left fielder Jason Bay probably would have caught.
The Pirates have lost six in a row since the All-Star Game.
The 27-year-old Izturis is in the final year of his $9.9 million, three-year contract. There is a 2008 club option for $5.85 million that can be bought out for $300,000.
Izturis, an All-Star with the Dodgers in 2005 before his season was cut short by elbow surgery, joined the Cubs at the trade deadline last season when Chicago dealt Greg Maddux to Los Angeles.
In 65 games for the Cubs this season, Izturis was batting .246 with eight RBIs. His playing time had diminished after Ryan Theriot took over as the No. 1 shortstop.
"I just want to play every day and now I get an opportunity to go to Pittsburgh. I don't know the situation over there, but I'm going to miss this team," Izturis said.
"There are a lot of good people around here. Good team, but it's business. ... I have to give credit to the young guys like Theriot and [Mike] Fontenot, they bring energy for the team," he said.
Izturis will be reunited with his former Dodgers manager Jim Tracy, who is now the Pirates' skipper.
"Good, especially with a manager that you played before with him and got your confidence. That's good," Izturis said.
Cubs manager Lou Piniella said he initially penciled Izturis' name into the lineup for Thursday's game against the Giants before the trade was made.
"Cesar was a really good guy. He wasn't getting much playing time here," Piniella said. "In fairness to him, let him go somewhere where he can play."
Theriot has emerged as the Cubs' shortstop with consistent hitting, good hands and speed. He was batting .278 entering play Thursday.
"Theriot really took over the job," Piniella said. "There is nothing wrong with Izturis. Izturis is a good player."
In 87 games with the Cubs, Izturis batted .242 and had a .968 fielding percentage that included nine errors in 273 total chances.
"Obviously we thought going into the season that he would be the starter," Cubs general manager Jim Hendry said.
"But the people that earn the most playing time get it. It's not an indictment of him. He's a wonderful guy. He still has a lot of ability. I just felt that it was a good situation for him to move into," Hendry said.
The Cubs also purchased the contract of catcher Jake Fox from Double-A Tennessee. He can also play first, third and the outfield.
Fox, who turns 25 on Friday, got Piniella's attention during spring training when he went into the manager's office and asked for more playing time in exhibition games.