The Little, or Secular, Oratory was the earliest form of the Oratorian life established by St Philip; the congregation of priests happened almost by accident, simply to serve the brothers. Since then, the majority of Oratories have tended to have a community only of priests and full-time brothers (as at Toronto) while others have the brothers in addition (as at the English oratories). Brother-only groups are not unknown, but they are not frequently to be found—though I discovered one by accident on Capri, with their own Little Oratory chapel under the sanctuary of the Cathedral in Capri town. Here in San Diego, the Little Oratory is flourishing, with nigh on twenty brothers and adherents, mostly young and energetic. Their particular work has, to date, been concerned with celebrating the liturgy (in both Ordinary and Extraordinary forms) well, with Gregorian chant and polyphony as the Church recommends. They have recently been giving some thought to extending their operation, in the spirit of St Philip, towards charitable work and study and discussion together. They are very fortunate to have the enthusiastic support of both His Excellency Salvatore Cordileone, the auxiliary bishop here in San Diego, and the community of the Little Oratory in London. The San Diego branch are now looking for a permanent home for their activities, as chasing from place to place is obviously unsatisfactory.
They have a blog here.