PHP rocks in this setting....I have built a couple of similar systems, with web based front-ends...Never had a problem with them...
As for the question of whether this is a good solution for small distributed apps, think of it this way....Lets say you have 10 workstations...and one web/db/etc server. You have one central location to control everything. Need to make a minor change? hey...its done...do a complete rebuild?...you only have one place to fix it. By centralizing your app, you cut down on your work.
The other major advantage I have found is that it can be made accessible to the whole world. This can also be quite dangerous (so be careful). But this is handy when you have doctor X, or patient Z or whomever, and they need info while they are NOT at the hospital. As I said, this does have some security risks, but they are quite easily managed.
Hope this helps
Darren
The hardest part of this is the UI. Well designed VB can give the user some greater flexibility as far as look and feel go. Either solution will work obviously...But for me, I tend to lean towards the web based solution.