An XDA forum member has complied an image of the Jelly Bean ROM, which is flashable on the existing GSM Galaxy Nexus via ClockworkMod Recovery.
Google pushed out a 12.6 MB OTA update, Android 4.1.1, for the new Nexus 7 tablet and GSM/HSPA+ Galaxy Nexus earlier this week. Here's how to install Android 4.1.1 Jelly Bean (Build: JRO03C) on Galaxy Nexus. Reuters

The latest Ice Cream Sandwich 4.0.4 update to Samsung Galaxy Nexus will load exciting features to the device. It will improve the system stability, enhance camera performance, and have smoother screen rotation and enhanced phone number recognition.

On the other hand, the Nokia Lumia 900 comes with a ClearBlack glass touchscreen with a sleek design. Users can enjoy blazing quick internet access even during streaming of videos. The Nokia Extras offers plenty of cool apps and maps. Users can have unlimited fun with Nokia Music which includes a Mix Radio and free streaming of music. Not surprisingly, both the smartphones possess breath-taking features.

Here s a rundown of how both the smartphone stacks up:

[1] Display

Nokia Lumia flaunts a 4.3-inch AMOLED ClearBlack touchscreen with a resolution of 800x480 pixels. The slim device is smooth and fabulous.

In comparison, the Samsung Galaxy Nexus is the amazing device which touts a 4.65-inch high-resolution AMOLED display. Users can have the best viewing experience.

[2] Processor

Nokia Lumia 900 boasts of 1.4 GigaHertz Scorpion CPU, Qualcomm APQ8055 Snapdragon and the Adreno 205 GPU.

In contrast, the Galaxy Nexus includes 1.2 GigaHertz Dual-core processor which ensures the quickest way to access the apps and ultra-fast web browser. It contains the PowerVR SGX540 GPU and TI OMAP 4460 chipset.

[3] Operating System

The stunning Nokia Lumia 900 runs on the latest Microsoft Windows Phone 7.5 Mango operating system. The sporting features are face detection for picture tags, Facebook and Twitter Integration, Zune SmartDJ mix support and more.

The Galaxy Nexus runs on the Android 4.0 operating system. It is now upgradable to the latest Android 4.0.4 Ice Cream Sandwich.

[4] Camera

Nokia Lumia 900 comes with 8-megapixel rear-facing camera which features Dual LED flash, Carl Zeiss Optics, auto focus and touch focus. It offers 1.0-megapixel VGA secondary camera for video calling and 720p video recording. Moreover, users can enjoy video calling, thanks to Tango Video Calls which is preinstalled in the device and allows in making the video calls over Wi-Fi.

On the other hand, the Galaxy Nexus comprises a 5-megapixel rear-shooter and 1.3-megapixel front-facing camera. It offers 1080p video recording.

[5]Connectivity

Nokia Lumia 900 includes Wi-Fi 802.11 b/g/n and a Bluetooth 2.0 technology. Its speed consists of HSDPA 42 Mbps and HSUPA 5.76 Mbps.

While, the Galaxy Nexus includes Wi-Fi 802.11 a/b/g/n with Wi-Fi hotspot. It speed is comprised of HSDPA 21 Mbps and HSUPA 5.76 Mbps.

[6] Battery

Nokia Lumia 900 comes with a Li-Ion 1830mAh Standard battery which allows the talk-time of up to 7 hours in 2G and 3G. The stand-by time is of up to 300 hours in 2G and 3G devices.

In comparison, the Galaxy Nexus boasts of Li-Ion1750mAh battery which ensures the stand-by time of up to 290 hours and 270 hours in 2G and 3G respectively. The talk-time is of up to 17 hours 40 minutes in 2G and 8 hours and 20 minutes in 3G.