1) I wondered if I could use Pearson's to obtain point biserial coefficients if the data is non parametric?

2) Failing the above, how do I (quickly) obtain rank point biserial correlations using SPSS?

One paper suggests using Mann-Whitney tests to get the mean rank diff scores and the signficance levels. The biserial coefficient correlations are then to be computed by multiplying the mean rank difference scores by two and dividing by the sample number (Chmura Kraemer, 2006; Nichols, 2000). This seems quite time consuming given the number of variables I have. Any thoughts or advice appreciated. I have 3 different samples of N=79, N=238, N=317