Due to a large number of requests, we've outlined the 'Registration Tools' area of the Student page within myOSU to help advisors guide students through getting set up.
This is the page students see (the registration tools section is highlighted):
(Click for larger image)
Please read below for specific information.

-General Registrar new Student information page
http://oregonstate.edu/registrar/getting-started
-Online Services Check your Registration Status page
http://infosu.oregonstate.edu/login
-Online Services Select Term page; Leads through to Look-up Classes to Add page
http://infosu.oregonstate.edu/login
-Online Services page for Adding/Dropping courses
http://infosu.oregonstate.edu/login
-General Catalog page, listing Baccalaureate Core Courses
http://catalog.oregonstate.edu/bcc.aspx
-Registrars rules/regulations on changing a courses grading basis
http://oregonstate.edu/registrar/change-grading-basis
-General Course Catalog page
http://catalog.oregonstate.edu/Default.aspx?section=Course
-Schedule of Classes Searcher
http://catalog.oregonstate.edu/SOCSearcher.aspx
-Available tutorials from the Registrar for using many common online tools