Hi !

I want to the difference between two Android operating system one is Eclair and the second one is Gingerbread. How these two Android different from eachother plz help me guyz m waiting for your reply ! :\

Best way is to see their changelog, it is log where you can see what have been changed , here is I found it online :

v2.0
The Motorola Droid introduced Android 2.0.

On 26 October 2009, the Android 2.0 SDK – codenamed Eclair – was released, based on Linux kernel 2.6.29.[22] Changes included:[23]

Expanded Account sync, allowing users to add multiple accounts to a device for email- and contact-synchronization
Exchange email support, with combined inbox to browse email from multiple accounts in one page
Bluetooth 2.1 support
Ability to tap a Contacts photo and select to call, SMS, or email the person
Ability to search all saved SMS and MMS messages, with delete oldest messages in a conversation automatically deleted when a defined limit is reached
Numerous new camera features, including flash support, digital zoom, scene mode, white balance, color effect and macro focus
Improved typing speed on virtual keyboard, with smarter dictionary that learns from word usage and includes contact names as suggestions
Refreshed browser UI with bookmark thumbnails, double-tap zoom and support for HTML5
Calendar agenda view enhanced, showing attending status for each invitee, and ability to invite new guests to events
Optimized hardware speed and revamped UI
Support for more screen sizes and resolutions, with better contrast ratio
Improved Google Maps 3.1.2
MotionEvent class enhanced to track multi-touch events[24]
Addition of live wallpapers, allowing the animation of home-screen background images to show movement

[edit] v2.0.1

The Android 2.0.1 SDK was released on 3 December 2009.[25] It was a minor platform release deployable to Android-powered handsets, including minor API changes, bug fixes and framework behavioral changes.[25]
[edit] v2.1

The 2.1 SDK was released on 12 January 2010.[26] It was a minor platform release deployable to Android-powered handsets, including minor amendments to the API and bug fixes.[26]
[edit] v2.2.x Froyo
Google's Nexus One was the first smartphone to receive Android 2.2 Froyo.
[edit] v2.2

On 20 May 2010, the Android 2.2 (Froyo) SDK was released, based on Linux kernel 2.6.32.[27][28] Its features included:[27]

Speed, memory, and performance optimizations[29]
Additional application speed improvements, implemented through JIT compilation[30]
Integration of Chrome's V8 JavaScript engine into the Browser application
Support for the Android Cloud to Device Messaging (C2DM) service, enabling push notifications
Improved Microsoft Exchange support, including security policies, auto-discovery, GAL look-up, calendar synchronization and remote wipe
Improved application launcher with shortcuts to Phone and Browser applications
USB tethering and Wi-Fi hotspot functionality
Added an option to disable data access over mobile network
Updated Market application with batch and automatic update features[29]
Quick switching between multiple keyboard languages and their dictionaries
Voice dialing and contact sharing over Bluetooth
Support for Bluetooth-enabled car and desk docks
Support for numeric and alphanumeric passwords
Support for file upload fields in the Browser application[31]
Support for installing applications to the expandable memory
Adobe Flash support[32]
Support for extra-high-PPI screens (320 ppi), such as 4" 720p[33]
Gallery allows users to view picture stacks using a zoom gesture

[edit] v2.2.1

The Android 2.2.1 update was released on 18 January 2011, and included a number of bug fixes, security updates, and performance improvements.[34]
[edit] v2.2.2

The Android 2.2.2 update was released on 22 January 2011, and fixed minor bugs, including SMS routing issues that affected the Nexus One.[35]
[edit] v2.2.3

The Android 2.2.3 update was released on 21 November 2011, and consisted of two security patches.
[edit] v2.3.x Gingerbread
Google's Nexus S introduced Android 2.3 Gingerbread.
[edit] v2.3

On 6 December 2010, the Android 2.3 (Gingerbread) SDK was released, based on Linux kernel 2.6.35.[36][37] Changes included:[36]

Updated user interface design with increased simplicity and speed
Support for extra-large screen sizes and resolutions (WXGA and higher)[33]
Native support for SIP VoIP internet telephony
Faster, more intuitive text input in virtual keyboard, with improved accuracy, better suggested text and voice input mode
Enhanced copy/paste functionality, allowing users to select a word by press-hold, copy, and paste
Support for Near Field Communication (NFC), allowing the user to read an NFC tag embedded in a poster, sticker, or advertisement
New audio effects such as reverb, equalization, headphone virtualization, and bass boost
New Download Manager, giving users easy access to any file downloaded from the browser, email, or another application
Support for multiple cameras on the device, including a front-facing camera, if available
Support for WebM/VP8 video playback, and AAC audio encoding
Improved power management with a more active role in managing apps that are keeping the device awake for too long
Enhanced support for native code development
Switched from YAFFS to ext4 on newer devices[38][39]
Audio, graphical, and input enhancements for game developers
Concurrent garbage collection for increased performance
Native support for more sensors (such as gyroscopes and barometers)

So you can see the difference in each version hence all features and improvements from version 2.1 to 2.3 is the answer to your question.