Ventrilo is a simple program with a simple purpose, but a tedious setup for the first time user. Here's a quick little blurb on setting it up to your liking and to prevent from blowing another Ventrilo user's ear-drums.
First you want to start by setting up your name, and phonetic if you want one.
Next, we setup the destination server by inputting the IP and port of the server. This is where you can toggle whether or not to recieve "Pages" from other users and whether or not you want others access to record your voice by checking, or un-checking the boxes.
Now that the Name and Server are done, you should setup your sound scheme, you don't want to connect and blows someones ears off with the wrong setup, or have no one hear you in the first place...
That is the basic Ventrilo setup screen, and usually the most dreaded for the squimish...
Begin by selecting your Mixer, the drop down menu will display the sound card(s) in your system. Just select the sound card that your microphone and speakers are running off of and it will usually fill in Mux and Microphone accordingly.
Now in the top right-hand corner for your Output Device, selet 'Use Direct Sound' and use the drop down menu to select your sound card.
Now do the same for Input Device.
Now you can setup your speaking control, as to whether or not you would prefer your microphone to be voice activated, or if you want to have it 'Push to talk' (Which in my opinion is alot better!). Also, remember to un-check 'Play Click Keys', as it is a very annoying little feature to remind you that you are talking.
Now go to the miscellanious tab and set the options to your liking, such as 'Minimize to system tray', and auto-expanding all channels when you join the server.
There you go! The hard stuff is done! Now you just have to join a server and set your Input and Output volumes to your, and the other server users' liking!
Good luck!