Per the Gravestone Image on the Arlington National Cemetery website
Army Captain Ian P. Weikel
October 7, 1974
April 18, 2006
He was 31 years old at the time of his death. He was assigned to the 10th Cavalry Regiment, 1st Brigade Combat Team, 4th Infantry Division, Fort Hood, Texas. Captain Weikel died April 18 in Balad, Iraq (42 miles North of Bagdad), from injuries sustained when an improvised explosive device detonated near his Humvee during combat operations in Baghdad.
I also have reason to believe that the "buddy" from this web image that has been circulating is his brother. This photo was captured as part of a news story about Section 60 at Arlington National Cemetery by the LA Times.
http://articles.latimes.com/2010/nov/11/nation/la-na-arlington-war-widows-20101111"It's a perfect autumn Sunday and Chad Weikel is sitting outdoors, having a beer with his big brother, Ian. Chad's beer is resting in the cup holder of his folding chair. Ian's is propped up against his headstone.
Army Capt. Ian Weikel, 31, was killed in action in Iraq on April 18, 2006, so this is how they visit now.
....It's getting cold. Chad Weikel, 33, and his girlfriend, Kate Thompson, 31, finish their beers. He lives nearby and figures he's done this at least 75 times since his brother died. He doesn't feel like talking much. "When I first came here, it was really hard. But it's a community and a family. Days like Memorial Day, there are 200 people having picnics. And then there are days like today, quiet and beautiful."
They carry their chairs to the black Chevy truck that used to belong to Ian. An unopened bottle of Texas-brewed Shiner Bock stays behind, a nod to his unit at Ft. Hood."
This is a photo of the brothers together in happier times...

RIP Captain Weikel