Went for an oil change, and had them drain the Transmission fluid, and refill.
I noticed later on in the day that it is slightly above the mark, on the dipstick. I checked it with the engine on and in park ( assuming this is the correct method).
Is too much fluid a problem? Should I let some out or is it Ok to drive like this??

Thanx in Advance

 

Slightly above the mark is no problem. If it is grossly overfilled, it will probably spill out at some relief valve somewhere in the transmission. There are tales that excess ATF causes pressure buildup and the transmission seals get all messed up, but that's not true. The biggest danger is probably if it is too full (which yours is not), then it might spill out the dipstick tube and possibly cause a small engine fire under the hood. But that's highly unlikely.