At 10;000 FT after takeoff a Q-400 Master Warning alerted #2 Engine Oil Pressure Low and the #2 PEC Caution light illuminated. An emergency was declared; the engine shutdown and the flight returned to the departure airport.

Narrative

After an aborted takeoff for #2 AC GEN Caution light earlier in the morning we returned to the gate and turned the aircraft over to Maintenance. About 90 minutes later and an AC generator swap; we departed again. All indications appeared normal until at 10;000 and a Master Warning #2 Engine oil pressure light followed by a #2 PEC caution light. After noticing the warning light I referenced the #2 oil pressure to be roughly 33 PSI and dropping. The Captain called for 'Low Oil Pressure' Checklist which was referenced until it was decided to shut the engine down. We shut the engine down; declared an emergency and landed without further event on. Amidst the increased workload and distractions; I began to run the wrong checklist but realizing my mistake (the oil pressure was below 44 PSI which calls for an automatic shutdown) I was a little slower than I should have been in shutting the engine down. Having the QRH in my hand as a result of running the low oil pressure; we secured the engine per the QRH. Our proximity to the airport was pretty close and almost immediately after the issue was detected we were in a left turn returning to the field. While all the checklists were being run and coordination between ATC attended to; we were not able to make a PA announcement to the passenger and flight attendants. We did receive a call on the flight deck informing us the right prop had stopped turning and I told our flight attendant we were aware and I would call her back when everything settled down a bit. ATC handed us off numerous times and we attended to the radio calls interchangeably. After shutting the engine down per the QRH instead of by the memory items we backed everything with the QRH. After landing; and slightly relieved we taxied off the runway and into a holding pad were numerous airport vehicles and staff were assembled. We were asked to drop the nose gear doors. Unfortunately with everything going on prior to engine shutdown we weren't able to turn the PTU off and we weren't able to raise the doors after it was determined that the doors must be up for a super tug. Looking back on the event; I realize that there was really no need to hurry back to the airport as we did and wish I would have spoken up to allow us to run all checklists and communicate with the flight attendants and passengers. We weren't on fire and just a few minutes would've done no harm and would have allowed us the ability to make sure we were correct and safe to return to the field.