Lake Allatoon is north of Marietta a few miles, you can check gofishgeorgia.com for more information. There's been a big drought here since 06 so the water levels are much lower than normal.
The chattahoochee river is near, a section of it is DH for trout. Alot of good bank access but watch wading, they've been releasing alot of water and the flow is up.Check USGS graphs and the generally accepted wading level is < 5. There is also shoal bass (GA native). They are fun to catch and the chattahoochee river has some. GA started stocking them recently.
For more information on the chattahoochee river check out the NPS website http://www.nps.gov/chat/
you can also check out state parks at http://www.gastateparks.org/
good river fishing info on http://www.georgiariverfishing.com/
North GA has many trout fishing opportunites.
I usually chase only trout around this time of year.
- Dan M