A Canadian resident working in US for a US company

Hi All
I am a regular visitor to this site but this is my first post. I am a canadian resident (Permanent resident), and will be working for a US employer in a following way:
1) I have a corporate in Canada, and my corporate is contracting with a US employer to provide my services
2) I will be required to work in US (physically present for 3 to 4 weeks in US and coming back to canada for 1 to 2 weeks, working remotely during this time frame).
3) My status for USA is B1/B2 visa
4) I will be drawing salary from my canadian company.
5) The tenure of the contract will be one year
My questions are mostly related to taxes which are given below:
1) Do i have to file taxes (both personal and corporate) in both countries (US & Canada)?
2) Would i be in a situation where i would have to pay taxes to both the govt.(US and Canada) but i wil getting a refund from one of them?
3) I am very confused when it comes on taxation, and quite reluctant to accepting the contract. I would really like someone on this forum to help me and guide me through the whole process. Based on the guidence provided here, only then i would be able to make a decision to either accept the contract or reject it? Please help me out in explaing all the complexities aong the road.
6) Would there be any problems in regards to my US status (B1/B2) visa?
7) Finally if i have to file taxes in both countries, where would i save more money tax wise?

I would really appreciate your help and i hope that i would be able to make a quick decision to accept this opportunity but like i said i would be relying too much on you guys as i am totally confused at the moment. Please help and guide!
thanks

Yax forum at forums.serbinski.com is better place for me to answer this.

This is a travel site.

Did you find an answer for your questions?
I am in a similar situation I would appreciate having your feedback.
Thanks