writing DB polling application in visual basic 6

You will have to provide more info if we are to help you.  What does the structure of the SQL database look like?  Does the database contain the stock and min level and another database contain the live data (or does it come in by another source).  Basically, you will have VB pass a SQL query to the SQL database (such as "select * from stockdata where livedata.stockprice < stockdata.minprice").  Displaying this data in a data-aware grid is pretty straightforward.  

Please provide the info requested and we should be able to help you further.

The DB is Sql 2005.  For each item  min stock position is defined. I can retrieve the  current stock from soh table for each item by comparing it with min stock level for that particular item and display it in the grid. But my question is, i want to have vb application sitting on windows task bar (minimized) and continously poll the DB for this data at perioidic intervals and refresh the grid and give a pop up msg to the user of this data. I would be thankful to the experts if you could let me know how to develop this kind of application in VB.

In its simplest form, seems like a no-brainer. Like LowFat said, just poll the DB on a timer and update your grid. If an item is below min stock levels, display another form with its own timer that displays the info for a short period of time then unloads itself.

But you probably need more advanced functionality like LowFat is describing. If so, study his response thoroughly and work with him on this.