Despite many people saying .ws stands for 'website', in actual fact it is the country specific TLD for Samoa (see: hxxp://en.wikipedia.org/wiki/.ws) - swap hxxp for http!
So, if you choose to use a .ws tld for ranking in UK or USA, you won't be able to do things like set country-target in google's webmaster tools, and your site *may* be seen as a Samoa based site...
It would be the same as going with a .co.uk domain when targeting USA...
Consider a .co domain, recently these switched from being a country based domain (Columbia - hxxp://en.wikipedia.org/wiki/.co ) to a non-country specific tld. swap hxxp for http!
Hope that helps to stop any newbies getting blagged!!!