I have a DTS package that contains lots of Execute SQL Tasks. To pass parameters to these tasks, I go to Package Properties, Global Variables tab, and define variables there.
There are two variables I use: a date and a type. They are both set before the Execute SQL Tasks run. They are set with an Active X script task. (ex DTSGlobalVariables("today").value = date())
In the tasks themselves, I put a question mark and associate it to the global variable.
This works for my team but there very well may be a better way!