Good advice from Sheikh. Some of the larger buildings though do not like cash -- too much of a hassle getting it to the head office.
As to places o look, most of us advertise in the Toronto Star. Saturdays are the big day. The Globe ads tend to be higher end condos in places like Yorkville or Habourfront and larger suites in older buildings in areas like Forest Hill and Rosedale (the former like the Gold Coast/LSD area amd the latter somewhat akin to the Lincoln Park/Gold Coast area but without the attendant attractions -- think of areas like Winnetka but on the subway).
Another option for renting is to come here and hit the pavement. High Rises tend to exist in clusters here and the property managers frequently post vacancy notices on the building since prospective tenants know this and will wander their preferred areas. Some firms list vacanies on their web sites but this is not as common as it should be. Yonge/St. Clair, Yonge/Eglinton and High Park are good choices, being both safe for you and the client and easy to get to. There are other, more convenient clusters as well, the Yonge/Carlton area for one. The Bay and Bloor Street area has loads of condos for subletting but, if this bothers you, you are more likely to have your clients walk through a phalanx of security guards there than anywhere else.
If you are considering buying, don't bother with a mortgage broker. The system is somewhat different here. Find a good buyer's agent. A few specialize in the, errr, self-employed and have their own network of financing sources. Avoid the desperate ones though -- anyone not making barrels of money in that business can't be good at it.
If you've any questions, PM me.