The Schwinn frame is cromoly, as Psimet2001 knew it would be, and which marks it as one of the better quality World Sports, and it looks to be in alright shape. Needs some lube on the chain...that might be what's creaking, not the BB. Those older steel frame have some elasticity and are reputed to be more comfortable, and less jolting to ride than the rigid aluminum frames on newer bikes like some of the ones you're looking at online. They also last forever.

Unlike jmarkley710, I wouldn't "lose the dorkdisk" (the plastic spoke protector next to the rear cogs). It's tricky to remove and the only problem with it is that it offends snobs . However, I agree...the suicide levers (brake lever extensions) are dangerous because they don't brake very effectively.