A Writer's Resource

Going to make a list here, so in case one goes down, you'll be able to access others.

Die rollers are great for making decisions a bit more random, or for coming up with specific numbers based on certain criterion, or even deciding how many children/siblings/spouses a character might generally have--there's no end to the ways these can be used, if you're a bit creative. :)

Hamete Virtual Dice Server - allows everything from D2 through D100, and several versions of some, as well as offering multiple die rolls in one roll for you to pull from.  Allows for modifiers, though for people not familiar with RP or math, this one might seem a bit complicated.

Dungeons & Dragons Dice Roller - Allows for the usual dice D4 through D100, as well as one you can assign a value to yourself, and allows for multiple rolls of the same die at once, as well as additional modifiers.  Also records all rolls until the page is refreshed.

Konkrete Dice Roller - Allows the usual D4 through D100, multiple rolls, and modifiers.  Saves rolls and keeps record of the last 10 rolls.

Virtual Dice - a site that has D6 through D12 to roll

Random.org - allows you to roll 1 to 16 D6

Virtual Dice - allows you to roll 1, 2, or 3 D6, or one D6 and one with plusses and minuses

Unpractical Math Virtual Dice - allows you to roll 1 to 25 D6.

Hamete, D&D and Konkrete are the best of the group, but the others are definitely worth using for backups.

And for more, just google "virtual dice" or "online dice."