aggregate read cycle info from bam files

[osenan]

Hi Everyone:

I am trying to obtain this plot from some SNPs of my samples. You can see the plot in 8.52 of this video (R.Irizarry group) :

http://www.youtube.com/watch?v=eXkjlopwIH4

Basically, I need to know the cycle of each aligned read in a given position. I am thinking in indirect solutions ( I am using Illumina reads, 90bp ) but I was wondering if anyone have done these plots, or know some tool to directly extract this information ( in principle from a Bam File ).

Thank you very much
Oriol