Statex: extracts statistics from R objects right into latex.

https://github.com/SachaEpskamp/staTeX

From the description:
This package can be used to extract and print statistical results in a TeX format for easy inclusion in Sweave.

Take a t-test.

t1 <- t.test(dv~group,var.equal=T)

Input it into sweave/knitr

\Sexpr{st(t1)}

Get this: t(334) =1.72, p < 0.01.

not bad and works with a number of objects--lm, anova, chi-square.