What type of notice do I have to give for a discretionary profit sharing plan which is currently integrated and we are changing to a cross-tested plan? What is the deadline if any for this?

You would have to notify the partcipants of the amendment....typically done by way of a summary of material modifications. Basically, tells the participants in plain english as to what got amended and how it's different. Generally must be provided b/f deadline for 5500 I believe. ON a different note, I assume the plan has a last day of the plan year employment requirement such that the allocation provision, ie integration, can be amended this late in the cal. year....???

Be sure your amendment does not cause problems under IRC 411(d)(6).