Is it ok to give the username and password of my wordpress blog to any seo company?? I mean they have to track my site, so should i give it to them??
Well if they are genuine and you are hiring them to do SEO for you site then of course yes. They probably need to install Google Analyticator plugin and other tools to track your site.
With genuine supplier this is not an issue. But you can ask them what they will do to track website? If they want to do setup with analytics/webmaster than you can do the same with urself. Just Follow the steps.