Lenghty startup procedure

[Horst Gassner]

Hello!

When my program starts there are many things to do. Therefore I want to
display some messages (e.g. which kind of thing is loading at the
moment).

I want to use the Pmw-MessageBar - which works fine if the
TKinter-mainloop is running.

What I intend to do:
# start mainloop
# automatically start initialization after mainloop is started

But how can I do this? Is it possible to start a command automatically
directly after starting the mainloop? 

Thanx in advance
Horst