Android is an open source OS ( operating system ) initially developed & now managed by Google. There is a large community of developers who contribute to developing this OS & even larger community who are developing software & application ( apps ) that can run on Android OS. Because of being open source & free, it is attracting many users. Many developers are developing software for Android mobiles and tablets and number of softwares is soon expected to cross the number of softwares on iTunes. The great thing about Android Market is that majority of the softwares are free – some create it for their own use and others for money through Ads. Those apps that charge money, it is very minimal.
Downloading from Android Market is very simple. Just go to the Android Market from you mobile/tablet and logon using your Google id. In case you do not have a Google id you can create one on www.gmail.com .
However, precaution must be taken when downloading apps, as some of them may contain malware to get access to private information from your mobile/tablet which you normally do not want to share.