Are there any programs/applications that would allow a person to use a web browser while playing a game, like with Steam's Shift-Tab in-game browser?

It would be very handy for me to be able to view information and guides without having to constantly alt-tab.

For a game made in 1997? I highly doubt it, but maybe there are some dedicated modders who did something like that.

Doesn't have to be a mod, I would think there would be a stand-alone program that can duplicate the way Steam pulls it off for most programs.

Have you already tried running it through Steam with "Add a non-Steam game"?

Running through Steam's "add a non-steam game" option should work, though Evolve is another program that adds that feature and others. Both options work similarly from a technical standpoint, so if one option works, so should the other.