I have plans of visiting Montreal in a few days. I have to be there to arrange for my company�s event in the city. There would be some important guests and company executives. I have been asked to make some prior arrangements and so the thing I am concerned about is managing the traveling within the city. I know of some services that are worth a look, but if you people have any better options or sources for that, please let me know.

Actually, I have never been to Montreal, but I have been to Canada a few times. Here is my advice.
Customs in Canada: My experiences have been consistently very bad. Not that customs is fun anywhere, but my experiences upon entry have been notable bad, and my colleagues report the same. Hopefully you and your guests/execs won�t have that experience but if you think it is worth it to put the word out, do so. Especially if there are some attendees who have never traveled to another country. Have them make sure all their documentation is organized (passport, etc.) before they get to the agent, and tell them to be ready for the usual questions: Why are you here? What will you be doing? Where will you be staying? Where can you be reached?

As for traveling around a city I have never been to, the first call I make is to the concierge where you are staying, but do it before you get there so you can do some additional research on their advice. Find out what your options are, and then depending on the crowd you are entertaining, make your choice. If you are hosting people who are not necessarily flexible, public transportation is probably not a good option, with the exception of taxis. I like Sandrabullock's luxury car suggestion.
I have heard teh subway/train system in Montreal is excellentand easy to follow.
Let us know how it goes!!!