For students preparing for the PSAT/NMSQT this fall, the College Board has made a linear PSAT practice test available. This test is longer than what students who are taking the adaptive computer version will take but offers some excellent practice material.
Here is the link to the Digital PSAT Practice Test.
Here is the link to the Digital PSAT Practice Test Solutions.
Students preparing for the Digital PSAT can also use full-length Digital SAT practice tests since the timing and format of the two tests are identical.