Pinyin input method is now the most popular chinese input method.It is simple.I will introduce some pinyin input method software for you.Those software can help you input chinese characters easy.
1.QQ pinyin input method software
You may ask why this one is the first,because i think it is best.It can intelligent complete input,can update it's lexicon,can change it's theme simply.It's not will make you computer slow.This software can only use in windows.
2.sougou pinyin input
This software has more capable,has more nice theme,more lexicon.But it use more resouse.If you use an old computer,it will make your computer slow.But it also a good chinese pinyin input software.This software can only use in windows.
You can download it http://pinyin.sogou.com/
3.Google pinyin input software
It likes other google software,simple but enough for use.But it's updated for long time.Maybe google will stop suport it.This software can only use in windows.
You can download it http://www.google.com/intl/zh-CN/ime/pinyin/
4.unispim chinese pinyin input software
This software was ever the best pinyin input software.It use less resouse,and it don't use internet update lexicon.This software can only use in windows.
You can download it http://www.unispim.com/