I am an undergraduate F-1 student in the States.

Q1: I want to know whether I can apply for Canadian residency while I am staying in the States.
A1: You can apply for Permanent Residency in Canada if you meet the immigration criteria. You may find more information from CIC's website at www.cic.gc.ca

Q2: I heard there are some rules for getting points depend on the individuals. Can I know how to look up the rules of this sort? And, how much will it cost, if I apply the residency in the states?
A2: The immigration processing fee schedule is also available from the above site.

Q3: Now, how long does it usually take to get the residency.
A3: The processing time can vary from time to time based on the volume of applications being processed in a certain period. You can check the current processing time by visiting the website of the consulate where your application is being processed.