Segment a dataset session within a loop

Hello,
I'm trying to plot a large amount of records on google maps.  I want to be able to plot them in segments.  For example, if the dataset is rather large (10,000) records.  I would like to segment the dataset session of segments of 250, assign the lat and lon and add the markers then process the next 250 and so forth.  I've been able to come up with this but am still a ways away.  Any ideas?
Thanks,
J
int batchsize = 250;
                int numberOfEqualSizeBatches = ds.Tables["Contacts"].Rows.Count / batchsize;
                int size = 0;
                string id = null;
                decimal ...