Download the text file and rename it to end with .vb instead of .txt then simply add the .vb file to your project then declare a variable as a new instance of FileSizeConv then use the .CalcSize() sub to have it calculate the file size's then use the property for whatever you want shown to the user.
You can also feel free to modify it however you see fit, all of the math has already been done for ya.
And yes, I made Nibblets in VB.Net 2003. Whenever I get the time I'll re-make it in VB 2005 using 100% GDI instead of using pictureboxes displaying pre-set images like I did in VB 2003.