[R] Determining model parameters

[rkevinburton at charter.net]

This may be a begining question. If so, please bear with me. 

If I have some data that based on the historgram and other plots it "looks" like a beta distribution. Is there a function or functions within R to help me determine the model parameters for such a distirbution? Similarily for other "common" distirbutions, Poisson(lambda), Chi-Square(degrees of freedom, chi-square statistic), etc. For a normal distribution it is relatively straight forward as mean and variance can be computed failrly readily.
So far in my reading such parameters are more or less given but to do any kind of inference using a prior model it seems key that these parameters be at least estimated accurately.

Thank you.

Kevin