Single-entry visa allows one entry only to Canada within the validity of the visa.
Multiple-entry visa allows unlimited entries to Canada within the validity of the visa.
Transit visa allows for a short stop-over (maximum 48 hours) entry to Canada en route to another country. It can be granted for a single or multiple entries, depending on the applicant’s travel requirements. Example: If your return travel is also through Canada, you should request a transit visa valid for two entries.
Most of the information you need in Canadian tourist visa application (temporary resident visa) may be found here. Application forms may be downloaded here.
You may also want to consider the following tips on tourist visa application based on our experience:
1. Purpose of your visit. This is what I consider the most crucial part of your application. Why are you visiting Canada? Depending on your purpose, you may be required to submit a letter of invitation
2. Strong Ties to the Philippines. One of the major considerations by a Visa Officer whether to issue you a visa or not is if you will return the Philippines after the period given allowing you to stay in Canada. Considering the present situation in the Philippines and the opportunities in Canada, the Visa Officer may come up with 1,001 reasons why you will not return to the Philippines. If you're unemployed, within the working age bracket, and your purpose in visiting Canada is for instance to have a vacation, that sends a very bad signal.
3. Supporting documents. The Canada Visa Officer will review and make a decision on your application based on the documents you submit. It is important to submit sufficient verifiable documents.
The documents to be provided by the person inviting you to visit Canada varies depending on the purpose of your visit. For you to establish strong ties to the Philippines, proof of assets, employment, business, etc. is needed.
You may file your application direct to Canadian Embassy. Just follow the instructions in the application kit and submit the appropriate documents.
If you want to us to assist you on your tourist visa application, you may email me at firstname.lastname@example.org for your queries.
UPDATE (Jan 22, 2010): list of Requirements: Filipinos Visiting Canada.