There is hardly enough area to answer a question of this scope. The code you have will only read ID3v1 tags. This version held information in the last 128 bytes of the mp3 file. ID3v2 introduced dynamic sized data by means of giving each portion a specific header within the file itself. The downside is that you have to parse the whole file to extract all the relevent information. Hence the large scope of the question.
Fortunately there are a ton of projects/ActiveX/modules that have ID3v2 support you're after in VB6 format, residing in a little place called
Planet Source Code.
This is a haven for all beginners. I suggest you check it out, it'll answer all those pesky questions. Even Frodo gives it a thumbs up, so it's got to be good doesn't it.