Is there a convenient place to get vertical wind shear info for my location? Now that it's thunderstorm season here in New Hampshire, it would be nice to be able to find out what the vertical wind shear is like at the altitudes that affect thunderstorm formation, to guess whether they'll form.  Once cumulus clouds have started to form, it's usually easy to see by just looking up.  But when planning one's day in the morning, there often aren't big enough clouds yet.

Can anyone direct me to an easy-to-use source for this?
Yes, NOAA's Storm Prediction Center's soundings page is a great source for the information you are looking for, especially the skew-T diagrams and wind hodographs. This site provides current soundings as well as a past archive of 1 week. For the explanation of the soundings diagrams and numbers provided, see the soundings help page.