Wengo is a single application to talk, chat and share for free with anyone. Download is for Intel version. PPC version here (http://download.wengo.com/wengophone/release/2007-08-24/WengoPhone-2.1.2-macosx-ppc.dmg).

YSpeak is a free computer program for speech-disabled users. It is designed to assist in communicating in a variety of ways, reducing the input from the user to the minimum.

Telephone with real-time video

X-Lite is a premium SIP softphone with many PBX-like features. X-Lite features open standards-based design that allows for maximum network interoperation and integration. VoIP networks are expanding at a blistering pace, X-Lite is ready.

Friendz is an nice tool designed for seeing what your xbox live friends are doing without having to turn on your xbox.

Express Talk is another VOIP option for Mac users. It allows you to make free PC to PC calls and also supports PC to phone via a VoIP SIP. Express Talk is a free but full featured VOIP application with a wide range of features and functionality including multi-line support, caller ID, call recording and more.

With p990iCal you can transfer events from your phone to iCal and vice versa.

Ventrilo is the next evolutionary step of Voice over IP (VoIP) group communications software. By offering surround sound positioning and special sound effects on a per user, per channel, per server or global configuration level the program provides each user the option to fully customize exactly how they wish to hear sounds from other users or events.

iLingual allows you to localize other applications without using the complicated and difficult tools of appleglot. iLingual has easy to use drag and drop features, automatic save and a dictionary.

Proximity monitors the proximity of your mobile phone or other bluetooth device and executes custom AppleScripts when the device goes out of range or comes into range of your Mac.

Motorola RAZR V3c iSync Plugin is a plugin for Apple's iSync that adds basic compatibility with the Motorola RAZR V3c. The phone does not support iCal all-day events (because the phone doesn't understand them). Plugin only tested with the Verizon version of the phone. Requirements: iSync and Motorola RAZR V3c phone.

SightSpeed is a useful tool that provides video and voice calling services.

iPhone Remote is a small application that enables you to remotely access your Mac from your phone.

The SMS widget for Yahoo! (aka Konfabulator) allows you to send text messages to mobile phones. You don't even need to have a phone at all! It's free to send messages to the USA and Canada, and a cheap way to send messages worldwide.

Statz lets you modify your status across several apps all at the same time, from a single simple, yet powerful, interface. Currently it supports: Adium, Colloquy, Conversation, iChat, ircle, Skype, Snak, Tumblr, and Twitter.

Portable Adium is a multiprotocol instant messaging client that can connect to AIM, MSN, Jabber, Yahoo, and more.

With Serial Mail, you just put all the recipients into a group in your Address Book. Then, you create a draft of the email in Mail.app. Once it is saved as a draft, you highlight it and run Serial Mail. This app will create a separate email for each address in the group and send it along to that person.

This tool can be used to package and protect the digital content of your mobile phone. It also enables the use of mp3 files as ringtones.

TranslateIt can help you learn a foreign language or at least get you out of a bind when you find a word you don’t know. It can translate to and from English, Spanish, French, and Russian. You can also set it up to show the translation of any word under your cursor. This is a 20 day free trial.

Adium is a free instant messenger application. It’s a multiplatform messaging application for Mac OS X that works with AIM, MSN, Jabber, Yahoo, and more. Adium makes it neat and easy to use 1 application to chat with people on any number of IM platforms.