I have seen servers for 100 people how to do this

http://code.google.com/p/pyspades/

It appears to make the limit higher, but 32 is the actual hard-coded maximum.

(btw, I'm sure this belongs in 'Support', or in one of the other 'how to??' threads, but still it's a valid question for people that have not heard of pyspades)

how to use the pyspades

Well on the left hand side of that page it has Featured: downloads. There's a .zip with a win32 build inside.
Download it, and extract the files from the zip.
After that, go into 'config.txt' and edit the details (such as administrator password, server name etc), then use 'run.exe' to begin the server. If your port forwarding is setup right then it should display in the play list.
Inside the server you can use /login <password> to access the admin commands.