Alot of my reps work directly off of their tasks views when making calls. Is there a way to add some fields from the leads that the open tasks are for. For example, the emails on the leads or phone numbers?
No, not on the List View. Instead, you best bet will be to train Users to start using the out-of-the-box "Activities with Leads" Report [Activity Report] so that you can access fields from the related Lead record.