BTW, one more post and you'll be 1337.
Yes they will. But this depends on how the software is installed. Software installation is a really complex technology of it's own with the implimentation of MSI. Before that, it was pretty much file copies and shortcut creations. Now it's registered files and shortcuts. Admin accounts and User accounts, Advertised installs, per Machine and Per user installs. It's Not as simple as it once was.
If the software is installed per machine then any user can use it. If it's installed Per user, only the user that ran the install can use it (although it's possible to correct that), and if it's advertised, it's not installed until you launch the program. This all depends on how you configure the install as well as how the installer wrote the install program.
As to the roaming profile, you need to advertise the applications to the accounts. The computer configuration isn't captured with the Roaming profile. Most apps will install to all users, not current user, so that isn't captured in the roaming profile. If you advertise an application (the same program as the installed one) to a computer that already has it, nothing happens. If on the other hand you do it to a machine that doesn't have it, you will get a notification of new progams available from the start menu. When you run the program, it installs.
Besides, you don't want program installing from a roaming profile. That is wasted server space and time...