collocation methods

Hi R Users,

I have been trying to google (in general and specifically r-project) to see 
if I can find listing that may point me to understand the state of the art 
in R for functional approximation. Unfortunately, I have been unable to find 
anything concrete.

I hope I am missing something, and hence this message. Are there packages 
out there that may implement collocation. Specifically I am trying to 
implement Chebychev polynomial approximations.

Much more generally, has the R-management thought of some kind of 
encycopaedia that will allow developers/users to figure out what kinds of 
different routines are implemented and packaged under different packages?

thanks,
currently,

R Neeu B.