Photo credit: Orla

1. CalendarHub: Create and share a calendar that you can access from anywhere
2. Peekko: Chat with other people viewing the same site as you through the Firefox browser
3. Nimbuzz: Software that you can install on your mobile phone to chat and send text messages for free within a community
4. Pinger: Send instant voice messages to mobile phones from your mobile and from the Internet

1. CalendarHub
   
   
   
   CalendarHub allows you to create a calendar that you can access from anywhere. You can keep it private, share it with others or publish it on the web. You can find local events and add them to your calendar, get reminders by email or on your phone and invite others to your events. CalendarHub sports an Ajax-based drag & drop interface and provides RSS feeds for any calendar view. You can also subscribe to public calendars (e.g. through iCal) and import/export data from Outlook, Yahoo! Calendar and other services. Free to use.
   
   http://calendarhub.com/





2. Peekko
   
   Peekko lets you chat with other people viewing the same site as you through the Firefox browser. By default, Peekko connects to a chat server when Firefox loads. As you surf the web, Peekko queries the chat server for a channel based on the website you are viewing. You can join that channel and chat with other users who are at the same site. Free download.
   http://peekko.com/





3. Nimbuzz
   
   Nimbuzz is a software that you can install on your mobile phone to chat and send text messages for free within the Nimbuzz community. You can also chat with your buddies from other communities like MSN and Google Talk. To chat, or to have your buddies read your text message, you'll need a compatible phone (check the compatibility) and a GPRS and/or UMTS dataplan with your mobile operator. Free sign up.
   http://www.nimbuzz.com/





4. Pinger
   
   Pinger is a service that lets you send instant voice messages to mobile phones. Pinger is currently available only for North American mobile providers, but you can still send and receive messages from Pinger web interface, even if you don't have any mobile number. You simply need to log in with your email and a four digits pin of your choice: Pinger will send you a confirmation email and you will be enabled to log in as a guest. You can send a Pinger message to anyone with an email address. If they're registered Pinger members, they'll get a notification on their phone, email or both. If they're not registered, they'll get an email. During the beta period, the use of Pinger is completely free.
   http://www.pinger.com