Q.What Can I Do to Help My Tomato Plant
What can I do to help my tomato plant live and produce tomatoes? The leaves curl up, and the curled part is brown, stems very limp.

I have 4 varities of tomato's growing well and full of fruit and flowers. I transplanted the tomato's into a bed of potting soil then used mgrow and blossum end rot solution every 2 weeks. When some bugs showed and started putting holes in lower leafs, I started dusting with sevin dust.
I water twice a day, soaking the stems. My soil is sandy and it drains very fast so I put at least 1 minute of water on each plant from the hose shower then do it again after I finish watering the last plant. The tomato's are very tall growing out the top of the tomato rings. I am growing Best boy, Celebrity, hybrid high heat, and cherry tomato's. My cherry tomato's are already being harvested and my first Best boy is starting to color. All of the tomato's were transplanted about April 5th

It sounds like a type of wilt. Here's a video for you to use to see if that's what you may have:
http://www.youtube.com/watch?v=EOTi7srQJsY
If so, you'll need to move your tomato gardening area. Do not plant there again for several years. Take some leaves to your local nursery in a plastic bag and they may be able to help you diagnose.
You still have some time in the season (depending on your zone) to get new tomato starts (too late to grow from seed) and start a new tomato garden far away from the area your tomatoes are in now.

your tomatoes are lack of nutrition.. lack of nutritions to plants can't fight heat and cause chemical burn to leaves.. just give enough nutritions and it will give you many fruits just like my tomatoe farm.