Most corporate firewalls will ban websites such as logmein. However, they usually won't ban your home URL or your static internet IP address provided by your ISP.
Scenario 1 - Basic Firewall with Non-Restricted Access over HTTPS
For smaller enterprises, they might allow unrestricted outbound access over port 443. If this is the case, setup your home router to accept port 443(HTTPS) and redirect that to your local PC on port 3389(RDP).
Scenario 2 - Via Citrix XenDesktop
Citrix's XenDesktop Express is free and allow up to four concurrent users to connect to four remote desktop. It will require seperate servers though, ie
-Desktop Delivery Controller (DDC)
-Provisioning Server for Desktop
Scenario 3 - Terminal Services Gateway
Microsoft 2008 Server can act as a TS gateway and allow external clients to connect to the TS gateway and talk to computers behind the gateway.