I use IAGirl's gelatin pt, and it's done well for me. Cheap, easy, and customizable. The recipe is now off-site on Pedaheh's blog, and the thread about it on Curltalk is here. After you pt, if your hair feels dry, be sure to moisturize afterward. Not very dry and a protein free rinse out conditioner may work fine, more dry and you may need a deep moisture treatment.
CG since 11/2011
2c /3a F /Mii, low porosity

Spring Products /Routine:
Clarifying: Herbal Essences Tealightfully Clean
Low Poo: Renpure Luxurious Argan Oil
Co-washes: Suave Naturals Tropical Coconut or Daily Clarifying
RO:
Tresemme Expert Selection Perfectly (un)Done, Cure Care, Suave Tropical Coconut or Daily Clarifying
LI (if needed):V05 Kiwi Lime Squeeze, V05 Strawbery
Renpure Brazilian Keratin Straightening (old formula), Cure Care
Stylers: LALSG
PT: IAGirl's as needed