In order to install MindCrack, you'll need to download the Feed the Beast Launcher. Download either the EXE or JAR.
Download EXE Download JAR Official Download Page
Run the launcher and choose the directory that will hold all of your FTB files. All game files will be downloaded to this directory.
At the bottom right of the launcher, drop down the Select Profile box and select Create Profile to enter your Minecraft login information.
From the list on the left, select the MindCrack Pack.
Drop down the box at the top that says Recommended and change it to 7 to make sure that v7 is used. You cannot connect with other versions.
With your profile selected, click the Launch button at the bottom right.
On the first run, the launcher will download and install all of the MindCrack files. This may take some time.
The server can be reached at mc.opserve.net (assuming you're on the whitelist).
You can also connect to the Teamspeak at ts3.opserve.net (assuming you know the password).