It is simple to use the bitcoin currency conversion. Simply type:
$ btc to currency or
$ currency to btc. Example:
1 btc to USD and
1000 usd to btc.
The bitcoin data is provided by Coinbase (bitcoin digital wallet). The feature is first available to users in the US, Australia, Canada, India and UK. It will be rolling out to more markets in the coming weeks.
As far as I know, bitcoin has different value in different bitcoin markets as shown here. Bing’s bitcoin currency converter only gives you an idea how much bitcoin worth in your currency.
Coincidentally, bitcoin exchanges, such as MtGox, halt bitcoin withdrawals due to hacker attacks. Bitcoin price was peak at USD$1000 last year then stable around $800 but dropped below $700 after MtGox announcement.