I see that there is a SalesForce zimlet that allows you to import information on contacts and leads from ZCS to Salesforce. I also note that people have discovered that this doesn't work unless you pay Salesforce.com an arm and a leg for a high-end license.
There is a fabulous open source environment called OfBiz, and a quasi-commercial offshoot called Opentaps, that has enormous functionality in the ERP/CRM/SFA space which is a tempting target for a zimlet connector, especially for those of us who don't want to pay tribute to Salesforce.com. Ofbiz has a crude and largely ineffective email client built in, but I can't make it work in any useful way. Has anyone looked at an Opentaps connector? I am personally too inexperienced to write Zimlets, but I use Opentaps for leads ands sales tracking, and would be happy to help out on the "what is important to do" part if anyone wants to collaborate.