<table dojotype="dojox.grid.DataGrid" jsid="grid" id="grid" ><thead><tr><th field="0" width="225px" >Results</th></tr><th field="1" hidden="true"></th></tr></thead></table>
Did you ever figure out how to hide the Object ID field?
dGrid, the replacement for DataGrid, has a way to hide columns.
Like Ken Buja suggests, use dGrid instead.
With dGrid, you can hide a column when it is created or in css.
Since I don't know how to use DataGrid (anymore).
I think you may be able to use "hidden" as one of the parameters inside th tag with DataGrid.
Example:
<th ... hidden="true">Column Name</th>
<th ... hidden="false">Column Name</th>
Thanks.