Graphing Calculator you can use from home http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html
Scientific Calculator you can use from home Be sure to put calculator into degrees/radians depending on the problem http://www.mathopenref.com/calculator.html
This is can be used to calculate logs using any base. http://www.ajdesigner.com/phplogarithm/log_equation_base_any_y.php
This site will calculate the mean, median, and mode, as well as the standard deviation. You must enter all data separated by commas - not as a frequency table. You want the Population Standard Deviation. Note it also does Permutations and COmbinations. http://www.easycalculation.com/statistics/statistics.php
Regents Prep for Regents Review questions on any topic http://regentsprep.org/