Medved QuoteTracker works fine for realtime alerts with a maximum of 80 but is free. A good beginners software. QCharts from Quote.com works fine for realtime alerts with no maximum and includes good realtime charts to go alng with it. Also other things that make it much more versatile but costs about $70/mo.
green_lantern - alerts based on what kind of criteria - just price above/below X (which most any quote system can do) or more complex alerts? A couple general examples would help narrow your possible choices of alert software.
looking for alerts based on my own moving average crosses and also alerts based on price structure crossing moving averages haven't seen much that allows this regards , green