Question about service.

I want to develop a tool like tlist of windows 2000 or tasklist of windows
2003.
tlist and tasklist commands show lists of processes.
An example of tlist -s is following.

684 services.exe Svcs: Eventlog,PlugPlay
696 lsass.exe Svcs: NtLmSsp,PolicyAgent,ProtectedStorage,SamSs
872 svchost.exe Svcs: RpcSs
920 svchost.exe Svcs: TermService
1148 svchost.exe Svcs: Dhcp,Dnscache
1172 svchost.exe Svcs: Alerter,LmHosts

According to the result, we can identify main role(RpcSs, TermService, etc)
of each svchost.exe process.
How can i get lists of services of each svchost.exe.

Thanks in advance!