Need to write my first web application - scratching head

Hello all,

I'm a longtime programmer (embedded with a smattering of desktop stuff
as well) who knows very little about web programming. Right now I am
developing the prototype of a multi-user application in MSVC++, but I
think it would make more sense to redo the app as a web application
(which I know almost nothing about, remember). From poking around I
see that PHP is a fairly mainstream candidate for me to consider.
Now, I will continue to poke around in this group and on the web to
gather the fundamentals as to how I need to proceed, but in the
meantime I'm hoping for a few words of wisdom.

So, regarding developing a web application w/ a small database, what
are the key things I need to know? What are the key things I need to
avoid? How can I maximize my chances of success and minimize my
chances of throwing my computer off the balcony?

One requirement of this application is to be able to print from the
client computers, so I presume some code will need to be located there
as well as on the server. What is the typical way to do this?

Thanks for any and all tips.

Mike
.