Zipiko is a Free Online Event Planning Service that lets registered users to set up social plans & join events in their social network all with free SMS on their mobile phones .
Zipiko was developed in Python with Django and Sqlite & runs on the Google App Engine infrastructure. But more on the free event planner services from Zipiko.
Zipiko is available in English, Finnish, French, Italian, German and Spanish.
Using Zipiko is simple. You select a friend from your buddy list, pick a time and a pre-set location (or enter your own). A SMS or text message is then sent to your invitees and you are notified when they accept. Newly added is the support for groups to make inviting multiple people easier.

Although there isin’t calendar sync yet, Zipiko has the ability to include your Gmail contacts along with an iPhone sync. Although sending SMS event planning invitations is free from the service, individual mobile operators could charge for incoming SMS text messages depending on the service plans.
The technical team has also included a small introductory video on how Zipiko works .