I stumbled upon a great resource today for measuring currency strength.  There have been lots of talk on how to go about measuring this in forex forums for years.  The USD index on the NYBOT is determined by a basket of currencies but according to FuturesMag, overweights the EURO and includes the irrelevant Swedish krona.  A company, the International Index Company in conjunction with major investment banks have created FX indices for the AUD, CAD, CHF, EUR, GBP, JPY, NOK, NZD, SEK, and USD.  Each index uses a particular basket of currencies to determine strength or weakness.  For instance, the GBP index uses the following weighted basket of currencies:

• 66.59% EUR
• 21.47% USD
• 5.91% JPY
• 3.14% CHF
• 2.89% SEK 

The following is a GBP index graph over the last month:

I don't know how I can use this information to my advantage at this moment but if I can't, maybe you can.  You can find an accompanying article that details the IBoxxFX indices at Futures Mag.

To access the indices, you have to sign-up for a free account at http://www.iboxx.com.