ERJ on the O'Hare Three SID from ORD fails to comply with the 250 kt restriction sequestered in the fine print at the top of the page.

Narrative

On departure out of ORD; we were assigned the ORD 3 Departure Procedure; vectors to DENNT Intersection. Climbing through 10000 feet MSL; the First Officer accelerated the airplane to 290 kts. At 12000 feet MSL; ZAU instructed us to resume normal speed. I replied that we were already at normal speed (290 kts) as we weren't assigned anything else by Chicago Departure. The Controller replied that ORD 3 Departure has a 250 kt speed restriction until advised by ATC for aircraft flying over DENNT intersection. I then looked at the ORD 3 chart and found that the 250 kt speed restriction is noted in the upper right corner in fine print. I apologized to ATC and admitted that we did not see that prior to departure. She replied; 'No problem;' and mentioned that it was added when the ORD 3 departure was updated on Nov/08. I admit our mistake in failure to fully review and brief the Departure Procedure; and I have since highlighted the speed on my chart to ensure I don't miss it in the future when leaving ORD. I also feel that a speed restriction pertaining to a Departure Procedure ought to be more noticeable on a chart; i.e.; in BOLD print near the Departure Fix itself.