Here's a little trick we discovered for converting tab delimited text to comma separated (CSV). You'll need access to a Unix, Linux or Mac OS X machine as it relies on the 'tr' command line not present on Windows.
To convert the file simply :
$ tr '\t' ',' < file.tab > file.csv
where 'file.tab' is your tab-delimited file and 'file.csv' is the file to write to.
And you're done!