Getting Started with ISBoxer + Roblox
Multiboxing Roblox with ISBoxer:

The main annoyance (other than that there is no auto-follow, but this is not your usual MMORPG either) is that Roblox renders its own cursor, so it appears underneath the overlay. Otherwise, it works acceptably and you can try ISBoxer with all of your favorite Roblox games.
Setup for Roblox is fairly simple. I'll do a video, but here's a written guide for you to follow.
Before you can multibox Roblox with ISBoxer, you need Inner Space build 6633 or later, and ISBoxer 42.12.1029.1 or later. As of this post, Inner Space build 6633 is available under the Deveopment tab in the Inner Space Patcher window, and the ISBoxer update is available in ISBoxer Toolkit via Help->About ISBoxer.
Now for starters, Roblox games are launched by a browser. So the first thing you're going to do is add Internet Explorer (iexplore.exe) to Inner Space. To do so, right click Inner Space, select Add Game, and either drag Internet Explorer to the Add Game window or navigate to C:\Program Files\Internet Explorer\iexplore.exe (usually).
Then we want to add a flag to its Game Profile so that it will close iexplore.exe before launching the next character. That will look like this:

So to do this, right click Inner Space, select Configuration. Click the "Game Configuration" tab. In the first drop-down box, pick "Internet Explorer", and in the Profiles drop-down pick "Internet Explorer Default Profile". Then simply type "iexplore.exe" in the "Kill" box as shown. When done, click Apply and you can close this window.
Now we've just set up a Game Profile that can be used the same way any game launcher is used with ISBoxer Toolkit. (http://isboxer.com/wiki/ISBoxer_42:Quick_Start_Guide#For_a_game_requiring_a_launcher)
The ISBoxer portion of the setup is extremely simple. Use the Quick Setup Wizard and select "Roblox" from the first page. Add your Characters, they don't need to be accurately named; I just put in "roblox 1" and "roblox 2" for character names. Select the "Internet Explorer" Game and Game Profiles from earlier in the Inner Space game launch drop-down boxes.

Pretty much everything in the wizard can be left default. It will default to the "Generic Broadcasting" configuration style. Finish the wizard, Export, and launch your team!
The launching process will happen one character at a time. Each time Internet Explorer launches, go to roblox.com and log in to the next account and click play for one of the games. When the game client is launched, the browser should shut down, and the next one should come up. Just repeat until you're all logged in!