[R] how to calculate factor Scoring Coefficients

[Xingwang Ye]

Dear R users,
Recently, I am learning by myself to do factor analysis with R.
Could some one guide me how to calculate 'factor scoring coefficients' 
or obtain 'factor scores' with the results from principal( ) or 
factor.pa( ) function in psych package?
In SAS, it can be done with option "SCORE" by PROC FACTOR procedure.
Many Thanks.

felix