[pseut]

ChatSecure and IM+ both support OTR instant-messaging on the iphone, so depending on what you mean by "like that"... yes. ChatSecure is opensource too fwiw: https://github.com/chrisballinger/Off-the-Record-iOS

[mahyarm]

ChatSecure crashes so much it's unusable. IM+ OTR costs $6 and is closed source.