Very easy to get working.
Open Notepad, copy the attached code in to a file and save it as yahoo-stockquote.frm.
Make a new standard project in VB6. Remove the new form it automatically gives you. Load the components dialog and add MSINET.ocx ("Microsoft Internet Transfer Control"). Then load in yahoo-stockquote.frm to your empty project. Run it, and change Startup Object to Form1 if asked.
It had given you crap about LBound/UBound because you didn't have an array of textboxes. Any txtSymbol(x) textbox you create will be added to the loop in which to retrieve stocks. I made four in this example. Then I just created the other obligatory objects and set txtQuotes (receiver) to MultiLine=True so it can accept multiple lines of text. The txtSymbol textboxes are set to default to stocks Microsoft Corporation, ATI Technologies Inc., NVIDIA Corporation, and AMD.