The NRA plans to push the parking lot bill again next year:

There’s a lot of background noise right now in the continuing fight between the National Rifle Association and Georgia business leaders over the guns-in-the-parking-lot bill -- the measure that kicked up such a bitter fuss in the state Senate last session and was left to languish as the session ended.
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The parking lot guns bill – introduced as SB 43 but later incorporated into HB 89 – is part of a nationwide push by the NRA to prevent employers from making rules to ban their workers from keeping guns locked in their vehicles on company parking lots. It stems from an incident in Oklahoma. The NRA contends it is a Second Amendment issue. The Georgia Chamber, joined by many other groups, fought it to a standstill last session, calling it a violation of private property rights.

You’ll remember that it was twice sent to the Senate floor, but both times in the immediate aftermath of headline-making events involving guns. Despite threats of political retaliation by the NRA, the Senate both times dropped the bill to the foot of the debate calendar, effectively taking it out of play.
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The measure is still in the draft stages, we are told, but the approach could satisfy the Chamber of Commerce - many of whose leaders are sportsmen and NRA members - along with sportsmen’s groups who believe the NRA has lost sight of its broader goals through its fixation on parking lot guns.

But it probably won’t play well with the NRA. Last we heard, the guns-in-the-parking-lot bill was still their No. 1 priority, and still an issue on which they plan to rate legislators for the upcoming ’08 elections. To some lawmakers, the threat is a big deal.

The NRA did a lot of damage to itself by pushing this issue last year. They caused many Senators who wholeheartedly support the Second Amendment to take a stance on a bad bill.

This is an issue of choice for the property owner. If they don't want guns on their property, then that should be between them and their employee.

[UPDATED AND PROMOTED (by Josh)] I was doing some browsing of Georgia blogs, and I found the Georgia Law blog. In this post, the author notes an Oklahoma law similar to the one the NRA is pushing here. The result in Oklahoma:

U.S. District Judge Terence Kern issued a permanent injunction against an Oklahoma law that would have kept employers from banning firearms at the workplace under certain conditions.

Kern decided in a 93-page written order issued Thursday that the amendments to the Oklahoma Firearms Act and the Oklahoma Self-Defense Act, which were to go into effect in 2004, conflict with a federal law meant to protect employees at their jobs.

Kern said the amendments "criminally prohibit an effective method of reducing gun-related workplace injuries and cannot co-exist with federal obligations and objectives."