I haven't worked with the Apex Batch capabilities yet... it looks like the batch size is set to 200. However, some limits are lower than that -- such as the number of callouts allowed in a transaction (10). Is it possible to change the batch size to a lower number?

Basically, I need to run through all of the records of a particular object that meet the criteria, and for each, call an external web service (callout) and update the record accordingly.

And incidentally, it seems that the query/callout logic and the update logic would have to -- or could -- use different batch limits.