Look at your cutie little baby plants!

You know, cilantro and parsley like the cool weather. I have some growing outside now. I can't believe they've survived the 20-some degree temps!

However, these plants have been there since last summer. They have acclimated to the changes. Since your seedlings are so young and were started indoors, I'm not sure what you should do. My gut is saying put them out after the last frost. But perhaps they could go earlier if you "harden them off." I'm not sure how to do this specifically, but it is a process of gradually getting young plants used to the colder weather.

I would wait for some of the experts to answer. GGG and Esh are gardening gods. :)

They need to be transplanted NOW by the look of them. They are straining to get to the light, and will become too floppy and fall over.
Tomato, Squash and cucumber seeds are summer vegetables and really should not be set out until at least April 10th, which is our last frost date in the Atlanta area however, you need to check with the 10 day forecast then, to see how low the temps are going.
You will need to harden off your plants before then, since you started them indoors.

My recommendation for you is to get a good book on vegetable gardening and read it, now, as your plants mature or take a class on how to start your garden. There are many of them now. The library has some excellent books.

UGA Extension and your local extension office will also be stocked with lots of great information that you will need such as soil prep, where to site the garden etc.

http://apps.caes.uga.edu/urbanag/Home&Garden/indexFS.cfm?section=Vegetable%20Gardening

The calender link is broken, so here it is: http://www.walterreeves.com/uploads/pdf/vegplantchart.pdf

You can start seeds of cilantro, parsley, all brassica plants, all allium plants, lettuce, aurugula inside(right now, could have done earlier ) and once they have few true leves(or bigger) tranplant them in your garden.Do not worry about frost for these.
But you can also wait a couple of week (more or less) and direct sow them, if you are not impatient.
Cucurbita are best direct sowed, but you can also start them inside first week of April (inside or in cold frame) then transplant them.
You can also direct sow radishes, fenugreek, spinach and peas right now.Again, do not worry about frost in the future.
You can plant potatoes right now, cover with about 3 inches of soil and throw a blanket of leaves on them to keep them warmer and prevent possible fros bite to the seeds.

Next item to transplant would be tomato seedlings when danger of frost is over. But if the weather warms up nicely before April 10, you can do transplaning BUT be prepared to protect them (cover) in the event of frost.

Peppers come next. Transplant them in mid May.
Eggplants, basils and are probably last to transplant in JUNE. I would direct sow cucurbita at the same time.

NOTE:
I sowed my tomatoes, peppers, egplants in cold frame last year and I got good crops but not so early though.
I have been experimenting on winter sowing with bunch of vegetables like parsley, cilantro, dills, and basils.
I have yet to wait and find out the results. In the meantime I have sowed some seeds inside and in cold frame as well. So I am not betting on a single method.

Oh yeah. Cyrus is the other gardening god. These are my "Big Three" when it comes to super-helpful answers!!!!!

:)