Trimming a glued-up panel to width is pretty easy. Just set the rip fence on the table saw and run the straight edge against the fence. But crosscutting the panel to length presents a small problem -- the panel doesn't have a straight edge to ride against the rip fence.
So, in order to create a straight edge, I attach a framing square to the panel with double-sided tape so that the square extends over the edge (see Illustration). This way, the square rides against the fence as you trim the end.
To cut the opposite end, just remove the square and run the cut edge against the fence.