Open /Applications/Automator.app
, select to create a new Service, double-click Run AppleScript from the Utilities library, and enter the following script code into the text field:
on run argv
tell application "Safari"
make new document at end of documents
set URL of document 1 to "https://translate.google.com/#view=home&op=translate&sl=en&tl=es&text=" & item 1 of argv
end tell
end run
Save as Translate to Spanish.
Now you can select text in any application, and select Translate to Spanish from the context menu, or the Application » Services menu. A new Safari window will open, with the selected text as input to Google Translate.
You can assign a keyboard shortcut in System Preferences » Keyboard » Keyboard Shortcuts » Services.
Selecting from context menu (it's a submenu since I have too many applicable services, you can disable some in System Preferences):

The following page opens after clicking the menu item:

Are you looking for specific features, or does a basic service hacked together in 5 minutes suffice? – Daniel Beck – 2011-06-13T10:09:56.740
I'm looking for program that give me easy way to use google translate from any place in osx like it do translateclient.com under Windows. – diimdeep – 2011-06-13T10:15:23.810
Just a hint, the people most qualified to answer your question likely don't even have a Windows machine. "like this other thing you've never heard of and can't even try yourself" is therefore not a good idea if you want good answers. – Daniel Beck – 2011-06-13T10:25:02.253
1Google has *deprecated* the Google Translate API, so there's unlikely to be nicer solutions than the one I suggested, that will still work in 2012. – Daniel Beck – 2011-06-13T13:11:15.050
2
UPDATE June 3: In the days since we announced the deprecation of the Translate API, we’ve seen the passion and interest expressed by so many of you, through comments here (believe me, we read every one of them) and elsewhere. I’m happy to share that we’re working hard to address your concerns, and will be releasing an updated plan to offer a paid version of the Translate API. Please stay tuned; we’ll post a full update as soon as possible. http://googlecode.blogspot.com/2011/05/spring-cleaning-for-some-of-our-apis.html
– diimdeep – 2011-06-13T13:15:29.143Nice find. You should post this as answer, even though you might need to pay for Translate. – Daniel Beck – 2011-06-13T13:19:52.457