6 months ago Google launched a new service to all Google Apps users, The Google Apps Marketplace.

The Apps Marketplace allows third party companies to develop their own apps that can be integrated into the Google Apps interface to provide further features and functions.

In the past 6 months over 200 apps have been made available and the number continues to grow every week.

More than 4 million Google Apps users have third party apps installed and are enjoying their features. If you are not one of those 4 million maybe we can entice you with our overview of the 3 of most installed Google apps. Here is our countdown…

In third place: Insightly – A Free simple CRM and Project Management tool

Insightly is a free, basic CRM and project management application that links directly into your mail, calendar, contacts and documents.

The core advantage of the system is the email management. All mail is sent and received through Google’s Gmail app. However each message sent and received is also logged under the contact; allowing you to easily view a full conversation history with each contact.

The next impressive feature is the automated address book. This automatically adds a contact when you receive an email from them and then automatically searches the web for any further details available for that contact.

However the app’s biggest flaw is its simplicity. Insightly has removed features some users see as key; such as linking an opportunity to a contact and layout customisation, which continues to push users to the more costly alternatives such as Salesforce.

In second place – Offisync – The best of Google docs & Microsoft Office

Offisync is an add-on for Microsoft Office 2000-2010 editions running on a Microsoft operating system.

Offisync allows you to save and load documents directly from Google docs into Microsoft Office. This provides the advantage of having all the functionality provided by Microsoft Office with the sharing and access anywhere advantages of Google docs; which is what most modern businesses require.

The downside of Offisync is that, to be able to view the documents in Google docs the files must be converted which can lead to formatting losses – or a loss of the benefits of working in the cloud because you have to download the document in order to edit it.

Also the product is advertised as free, however a majority of the features are only available after purchasing a premium version.

“http://www.google.com/enterprise/marketplace/viewListing?productListingId=3442+17116012818275486668&hp=mostInstalled”

In top position: Aviary Design Suite – Full design and media editing suite

Aviary provides a full design suite to fulfil your basic media needs.

The suite is made up of 4 areas:

The image editing package “phoenix” allows you to carry out layered image edits as you would in programs such as Photoshop or GIMP

“Raven” is a vector image editor, useful for creating logo’s, website icons and buttons. This is similar to products like Illustrator.

The image markup programs “falcon” and “talcon” allow you to quickly take screen shots and make basic edits such as cropping, and resizing. It also allows you to add basic shapes and labels.

The audio packages “Roc” and “Myna” allow you to create and edit music by forming loops which can be used for multimedia. You can then cut, amplify and equalise your audio to produce a finished piece.

The downside of all this free functionality is that you suffer extended upload times unless you forsake your image quality by reducing file sizes.