Barbara, if you go with cloud-based CRMs then just about every system can be integrated so long as it's compatible with Safari, Opera or whichever web browser your office uses as a standard.
We're all Mac and we use Pipedrive.com. It's web based, so you really don't need to worry about the OS. Pipedrive also have mobile apps and integrate into Google Apps if you use that. All round, we're very pleased with them.
Barbara, you can ry BPMonline CRM.
As a web-based system BPMonline CRM works in Safari for Mac OS.
The major benefit of the system is a comprehensive business process management engine. With new engaging interface the system is as simple as your favorite social network. Besides, the solution is delivered at an incredibly inexpensive price point.
Test-drive BPMonline CRM at http://www.bpmonline.com/autologin?locale=en or request live demo: http://www.bpmonline.com/company/feedback/presentation