Russia - Saint Petersburg Apartments: Reliable Agencies?

We are going to Saint Petersburg for a couple of weeks. Will probably stay in a hotel (already have a reservation) but then thought that perhaps we could find an apartment to stay instead. Does anyone know of any reliable agencies to rent an apartment? [We will not need a registration, by the way].

I used City Realty and was quite pleased:

http://www.cityrealtyrussia.com/

It was a nice apartment, right off of Nevsky. We had a group of people and it was much cheaper than all of us staying in a hotel. They can also set up transfers for you as well.

I have used introbyirina.com and was very pleased with the experience. The apartment we stayed in does not appear to be offered right now, but there are many good ones to choose from. Irina speaks perfect English. If you need help choosing an apartment with a good location just DM me, as I'm very familiar with the city.