eCos web site is rich in documentation but here are some additional HOWTOs to get you started.
#1 Get started with eCos.
#2 Setup Eclipse / GDB to use with an Hardware debugger.
#3 Using the eCos instrumentation feature to trace kernel events or user application.
#4 Find out the bottleneck in your application with GPROF.
#6 Framebuffer and MicroWindows on Synthetic target.