I've used this - very easy to use and very fast:
   http://www.codeproject.com/cs/database/CsvReader.asp

It seems to be supported (they fixed a bug for me) and has source if you
want to "mess". Performance wise, they quote:

"To give more down to earth numbers, with a 45 MB CSV file containing 145
fields and 50,000 records, the reader was processing about 30 MB/sec. So all
in all, it took 1.5 seconds! The machine specs were P4 3.0 GHz, 1024 MB."

HTH
Steve

Assuming each line has a carriage-return/line-feed at the end
(and it must, or readLine wouldn't work), here's an easy way
to read in a file and split the lines by Crlf into an array
in one fell swoop. I don't know what this would do with your
file, but it's free to try it. :-)

Dim crlfs() as String = {ControlChars.CrLf}
Dim lines() as String = _
 File.ReadAllText("c:\data.txt").Split(crlfs, StringSplitOptions.None)
Dim numOfLines = lines.Length

Thanks to Francesco Balena; I got this out
of one of his books, probably the VB2005 Core Reference.

Robin S.