I have 2 questions:

1) I use GDM as my logon manager- I would like to use some remote desktop program that will prompt me for a username/password or send me to the gdm prompt first before logging me in. Something like Windows terminal services. I'm not 100% sure if LTSP would do this.. I think that is more for thin clients connecting from a PXE boot.

2) I was wondering if there was an alternative to Citrix for Linux- not so much for terminal services and remote desktop but I would like to have the ability to use published apps.

I don't want to do X11 Forwarding... but something like that.

As far as terminal services goes, xrdp is good. If the computer is on, it will give you a login screen (nothing fancy) and then drop you into your standard graphical logon (such as the GNOME DE). Just like Windows remote desktop. xrdp is the server software and you can use rdesktop to connection from a client. Each client you connect from opens up a new session (so you can't connect to a session that has been opened on that PC or from another computer remotely).