For a while I've been using Sly Flourish's online 4E Dice Calculator for all my campaigns; it's quick and easy and I find it better to use than looking up the entries on a PDF and doing the math to adjust the die sizes. But recently - primarily due to that fact that I'm over my monthly broadband bandwidth limit by a crapload - I've felt the need to have the same functionality as the above web page but in an offline capacity.
So, for now, I've created the standalone application below. It's currently written using the .NET 2.0 Framework and is for use only on Windows machines, but I'm currently investigating making something Java-based so it can be used cross-platform. That's taking me a bit since, quite honestly, I've never written a Java application with a user interface (all the Java apps I've done have either been console applications, plug-ins, extensions and the like)... But I'm getting there.
I'm also considering making an Android applet as well, but that's uncharted territory for me.
I expanded my tool a little bit to include a d20 as an available die size. I know that might sound somewhat weird, but my expectation was to make the tool also support the "adjusted" damage equations provided by C. Steven Ross over at DMG42. The only reason I haven't fully implemented those yet is because I haven't been able to consistantly match his equations, but I may get around to that yet. In the meantime, you are allowed to use d20s to roll damage, and the system will warn you in cases where it's impractical (for example, using a d20 at level 1 is higher than the average damage, so it's not really permitted).
And if you click on the equation, it actually rolls it for you. It's pseudo-random and it doesn't use the means of generating random numbers that other die rolling systems use, but it's better than nothing.
I'd like to thank Sly Flourish for providing the online tool on which this is based. if I ever get around to creating an offline cross-platform version, I'll make it available in the same manner.
If you have any issues or suggestions on how to improve this tool, please let me know.