Cloud computing is now popularly accepted worldwide. Over the last few years, nearly all leaders in technology jumped into cloud computing market. Cloud computing firms that may possibly lead the market in 2011 are listed below.

Amazon
Amazon claims itself World's biggest selection. I thought it can also be one of the best cloud computing companies on the earth. Cloud computing, cloud storage, cloud databases, content delivery service, payment, monitoring - you name it. In case you require a good cloud provider with affordable price, you can't afford not to check Amazon.com's AWS.

Apple
Apple's strategy to cloud computing market is to offer iCloud service to end users. Using iCloud, people can synchronize a variety of contents such as the documents, contacts, email, music, movies, etc. to cloud, and open or play it from any iDevice, Mac & PC. I won't be amazed if iCloud grows to be very popular service. Apple now has hurdreds of millions of fans for iServices and iDevices.

Microsoft
Some people believed cloud computing may be the threat to Microsoft. Acknowledging the changing trend, the OS giant is attempting to gain ground among the lead cloud computing companies. Even though it is not really popular as Amazon's IaaS and Salesforce.com's PaaS, Windows Azure is a rapidly maturing PaaS.

Google
Google improved how people search and research information. The search giant once again improved the way we use our office application with their Google Apps which offer cloud-based email, calendar and documents for small and midsized enterprises to large corporations. Google recently launched Google Music Beta. It is a service that will allows you store your music online and provides instant access without having to sync between devices. It was also believed that Google may be resurrecting their cloud storage project, G-Drive.

Salesforce.com
Salesforce.com provides customer relationship management (CRM) products to enterprise customers. It is one of the most successful cloud computing companies delivering PaaS.

Dropbox
Dropbox, Inc. provides cloud storage to end users. It offers a number of user clients across different mobile and computer operating systems. It is really hassle-free to store and share files with Dropbox. Sending and receiving files to and from other people is quick and easy. Even via the mobile clients, users can listen to their music files and watch movie files saved in their account. Free customers will enjoy 2GB of storage. They can get up to 8 GB of free online storage by recommending their friends to join Dropbox. If you purchase $9.99/month subscription, you will get 50 GB of storage. You can also subscribe 100 GB subscription and large quota plan.

Box.net
Box.net is content management and online storage company. Box.net now provides 5 GB to free user, while the rival Dropbox offers only 2 Gigabytes. But Dropbox's customers can have as much as 8 GB absolutely free if they recommend others to join Dropbox. Box.net charges $15/month to get 500 GB cloud storage while Dropbox charges $9.99 just for 50 GB. That is a significant factor to consider. However Dropbox has larger variety of client software - Mac, Windows, Linux, Android, iPhone, iPad, Windows Phone, Blackberry etc.

SugarSync
SugarSync is an online storage company that provides software application to sync documents, graphics along with other content among different desktops (both Windows & Mac), and even routinelysave them on the web. SugarSync provides 5 Gigabytes of free web storage to each user.