MyDice is a full featured application that allows you to use from 1 to 25 dice with sides from 2 to 100. It features a roll history to keep track of your recent rolls and the ability to clear the history. You can roll the dice by clicking the "ROLL" button or simply shaking your phone like you would real dice. The app even includes rolling animation with sound effects. Both the shaking and sound effects features can be disabled in your preferences.

MyDice screenshots: