Kosher salt by definition is no different from ordinary table salt from a kosher standpoint. The difference lies in the fact that kosher salt, unlike regular table salt, does not have any additives except for a free-flowing agent such as sodium ferrocyanide.
Kosher salt has larger grains than ordinary table salt and as such must be measured differently.
Because the grains in Kosher salt are larger than that of table salt, it occupies more space but is equal in weight.
For this reason, it is best to use a scale if you need to use a different type of salt in a recipe.
You can also use the conversion chart at http://www.mortonsalt.com/article/salt-conversion-chart/ to figure out the conversions.
There are some issues with the kosher salt that you need to know..
It is not used in baking normally due to the fact that it does not dissolve as well unless there is ample liquid to facilitate it.