<p>Looking for an open source library, for C++, Java, C# or Python, for reading the data from Quicken <strong>.qdf</strong> files.</p>

<p>@Swati:  Quicken <strong>.qif</strong> format is for transfer only and is not kept up to date by the application  like the .qdf file is.</p>

http://www.west-wind.com/Weblog/posts/10491.aspx
And i know one other blog where the author was developing a parser for qfx/qif... lemme look it up... googling hasnt helped yet :(
Update: Found one more:
http://blogs.msdn.com/lucabol/archive/2007/08/31/parsing-qif-quicken-files-in-c.aspx