I have two genres in genre list Sound Track and Soundtrack, now I want to change all Sound Track ones to Soundtrack is there any easy way to do this instead of 'Get Info' method.
Go into your Library. Press the 'Browse' button at the top left-hand corner of the iTunes window. Now you should see three lists: Genre, Artist and Album. In the Genre list, select Sound Track. This will filter out everything except tracks with the 'Sound Track' genre. Now Select All (Command + A), then Get Info (Command + I), then type in Soundtrack into the Genre field.
As explained, you can do Get Info on all your tracks at once, which saves time. Look at the above posts for a couple different methods of how.
The actual info is stored in the ID3 tags of the file; I don't know a way of changing it other than Get Info, and whatever way there is (if there is any) would be far more time consuming.
Edit: Wow, three people posting simultaneously. Haven't seen that one before.
You can use Get Info on more than one track simultaneously.
Sort your library by Genre, Highlight all the tracks with the genre Sound Track, select Get Info, and change the genre. It will change for all the highlighted tracks simultaneously.