I’m taking the train into Chicago to catch a Cubs game next month. Can someone please give me directions to Wrigley via public transport (I know the El, if WGN is to be believed, stops right across the street from Wrigley) from Union Station & back?
Also, I’ll have a couple of hours to kill before and after the game. Is there a Barnes & Noble within walking distance of Union Station or an El stop between Union Station & Wrigley Field?
Walk east across the river to the Quincy/Wells stop. Take the Brown Line Train (outside track) to Fullerton. Transfer at Fullerton to Red Line. Take Red Line north (Howard direction) and alight at Addison.
Or… from Quincy/Wells, take the Orange Line (inside track) to State/Lake. Transfer from the El to the Subway (walk out the turnstiles, down the stairs, into the subway station), and take the Red Line north (Howard direction) to Addison.
Or…walk a little further east, to State Street, and catch the Red Line either at Monroe or Jackson. Take north to Addison.
Also, if you don’t feel like walking, there’s a couple of buses (the number 7 and 126 come to mind) that leave from Jackson and the River, head east, and can drop you off at the Jackson and State Red Line subway stop.
Personally, I would walk south to Jackson, and then east all the way to State. It’s about 3/4 of a mile. Also, there’s a Barne’s and Noble, right there, on the southeast corner of Jackson and State.
Easiest, in my opinion. And it gives you a good stretch of the leg down to State Street. 
Google has just added public transit info for Chicago. Here’s what they suggest.
Check CTA’s site http://www.transitchicago.com/ or this site http://transit.elevatedconsulting.com/redstatus.asp for service changes that might affect you.