Here are some options for you:
There's a Google Spreadsheet script that returns the exchange rate between EURO and a currency that you specify. Data is supposedly from the European Central Bank.
Open a Google Docs Spreadsheet.
Click Insert > Script > Search for ECBExchangeRate
** With quotes on the date
This will return the exchange rate between USD and EUR for the date mm/dd/yyyy. Unfortunately, the data source isn't updated.
Calculating between 2 Currencies:
For example, we want to get the USD/JPY rate for today. Get EUR/USD and EUR/JPY using the formula above. Divide the EUR/JPY rate by the EUR/USD rate. You get USD/JPY.
I don't believe such a function exists for Excel (at least by default). You can, however, set up a sheet that imports data from an online exchange rate table like the one on the Yahoo Finance page (finance.yahoo.com > Investing > Currencies > Currencies Investing > Cross Rates).
You can then setup a VLOOKUP or INDEX/MATCH formula to get the relevant exchange rates for you.
Create a new sheet (recommended).
Click Data > From Web > Enter the following URL:
Click the yellow arrow beside the exchange rate table. The arrow should turn into a green check mark. Click Import.
Click Properties. Under Refresh Control, specify how often you want Excel to retrieve new data, or pick Refresh data when opening the file. Click OK then wait for Excel to load the data.
To refresh the data, just hit Ctrl-Alt-F5.
Here's a sample spreadsheet:
The data on the Yahoo Finance Page is pretty limited, but it covers the most popular currencies. You can use other sources, such as:
The website http://www.xe.com/ucc/ has historical rate tables which you can consolidate.