If you stop using silicones, and can deal with some possible bad hair days in the meantime, the silicone will eventually wear off of your hair in about 4-6 weeks. If you don't want to wait that long, one shampoo isn't going to force you to start from square one (even if it's a sulfate shampoo). Sulfate-free shampoos (as suggested by an earlier poster) are considered completely CG.

Modified CG since 11/5/11
CLEANSE: VO5 Vanilla Mint Tea Clarifying, DevaCare No-Poo, CHS Treatment Shampoo
RO: DevaCare One Condition, SS Caitlin's Conditioner, Mop Top Daily Conditioner
LI: SS Repairing Protein Treatment, CHS Silk Leave-In
STYLE: Re:Coil, Curl Keeper, Deva Ultra Defining Gel, Curls Rock Amplifier and Strong Hold Mousse, Sweet Curls Elixirs Okra Gel and Hard Hold Gel, SS Curl Enhancing Jelly and Firm Hold Gel