CSV2QIF at
http://www.csv2qif.com converts CSV files to QIF format. Either save your XLS file as CSV or copy data in Excel to clipboard and paste directly into CSV2QIF (look for the Paste from clipboard button).
CSV2OFX at
http://www.csv2ofx.com converts CSV files to OFX format.
Both tools allow to review CSV mapping, save it and conveniently reuse.