Hey! I've just posted IC. Combat! woo!
I'm fine with the dm doing the rolls, or us doing our own (as I did there). Linking to Invisible Castle is really pretty straightforward:
you go here: <http://invisiblecastle.com/roller/>
enter your character name and the roll you want, and then hit return. The roll comes up, and you can cut-and-paste the URL into a post here (or link it using the "link" button, up there in the second row, to the right of the little envelope). It's about a minute's work per roll.
You can roll both to-hit and damage at the same time by separating the rolls with a semicolon but not a space, e.g.: 1d20+5;1d6+3 and then post both results (in this sample:
to hit 16, 6 damage if a hit)
For Advantage, you can do the same thing, separating the same roll with a semicolon ("1d20+1;1d20+1"), and just declare the result, thus:
1d20+1 (adv) =15, or (same roll)
1d20+1 (dis) = 4.
(you can do the same thing by just asking for two rolls (
like this), and there are other ways around it, but for simplicity, that's really the only technique you need, if people want to roll themselves.
(you can also see the urls list three successive numbers, showing the order I made the rolls, and also that no one else is playing games right now!)
Hope this helps!
(For those concerned about cheating, it's really easy to catch people who roll multiple times (there are stable urls that increase numerically, and so you can see all the previous rolls, and also the time of the roll; suspicious rolls are really obvious. )