Sencha is going to be Good Thing in Coming feature Full Fledged HTML5 Thing 

  it will run in only server installed on individual system that is XAMPP for running the sencha programs on any  individual machines.
  
 first thing we need to know About html5,Javascript and css3 and XAMPP server

  to create sample project in with sencha lib we need to do like same as cordova command like we have to do sencha upto now it is under developement the sdk tools are individually install and run some lttle bit confusing  

the IDE is not fully developed means we have individual tools for every part of  the project  developement like for UI Developement ,For Running,For Creating Project ,we need to install or know all tools in sdk

1).sencha SDK or Sencha Command .

2)sencha archietect,

3).xampp server 

These SDK's have to install in mac
or windows
  these sencha is not only for mac,windows also  ya thats it we can say cross plotform tools like phone gap,sencha . for any mobile  we can make applications 

http://www.sencha.com/

http://www.sencha.com/blog/hello-sencha-touch-2-2/

sencha EXT JS is for Desktop or mac applications and 

Sencha Touch is for small screens like mobiles,tablets and ipod,ipads like

http://www.sencha.com/products/touch/resources/

please feel free to share if any thing  went wrong.

ThankQ.