Ask Slashdot: Open Source Remote Application Access?

First time accepted submitter taikedz writes "Citrix Xenapp with Receiver/Metaframe allows publishing individual applications installed on a Windows server to users on remote machines. These applications open in their own windows, along side others as if they were installed locally. I am looking to do the same at home, with free software, publishing applications from Mac, Linux, and Windows machines (and yes, I've verified the license agreements for the apps I am going to do this with!). Up until now, the only alternatives I have found are full-on remote desktop login, not seamlessly-integrated. Can you recommend any tools that can achieve the goal of remote individual application access across platforms for free or at low-cost?"