Here is the info from the FBI's website about how to help ID the Boston Marathon bomber:
To Provide Tips in the Investigation
If you have visual images, video, and/or details regarding the explosions along the Boston Marathon route and elsewhere, submit them on https://bostonmarathontips.fbi.gov/. No piece of information or detail is too small.
You can also call 1-800-CALL-FBI (1-800-225-5324), prompt #3, with information.
All media inquiries should be directed to the FBI’s National Press Office at (202) 324-3691.
The FBI officially released the photos of the two suspects at a news press conference today. Special Agent in Charge of the FBI’s Boston Field Office Richard DesLauriers addressed the media at 5:00 p.m. at The Sheraton Hotel in Boston.