Well of course it's hidden, it's a secret! Apple didn't want to admit this for a while, but it's been out long enough that something's finally come of it. The new Macintosh LC can drive many standard VGA monitors from the PC world with the addition of a special cable. Considering that the LC is a low-cost color machine, low-cost monitor options are important. Apple addressed this with the 12" Apple Color monitor, but that monitor suffers from a large pixel size and thus a small amount of information on screen. People who've used it say that it's slightly larger than the 9" monochrome monitors.
However, you can buy some pretty good VGA monitors these days. The truly good ones run about the same amount of money as the excellent 13" Apple Color Monitor, but you can find perfectly reasonable screens for less if you poke around. You have a better chance of finding a good used VGA monitor than you do a used Macintosh monitor. It's likely that even a good VGA monitor will not have the same clarity and bright colors as a Macintosh monitor simply because the Mac and the PC deal with monitors differently and many VGA monitors aren't designed for use with the Mac (most PC-clone monitors use solid colors for the background color and the text color etc., whereas the Mac uses a standard grey color for the desktop (though you can change this) and applies spot color to selected objects and types of objects).
Apple won't help you avoid buying an Apple monitor, so you'll have to find or build your own cable. InfoWorld published a pin-out and wiring diagram in its 11-Mar-91 issue on pg 38, so if you're the enterprising engineer sort, solder away. Alternately, BMUG (the Berkeley Macintosh Users' Group) has a kit for those of you who don't like poking through electronics stores to find parts. If you are less enthusiastic about solder flux, you have a couple of options. NEC will send you a free cable to work with its 2A or 3D Multisync monitors (at least the 3D is a nice monitor - I haven't seen the 2A). More generally, you can buy a $40 adapter from James Engineering, Inc. The MacVGA sits between the Mac and the VGA monitor cable.
To reiterate: test any monitor before you commit to buying it (though in this case, you may have to buy your cable before buying your monitor in order to run the test). Not all VGA monitors will work, and the more expensive SuperVGA and UltraVGA monitors will not provide better than 640 x 480 resolution.
If Apple would offer the two-floppy drive LC to normal people (as far as we know, only educational departments can purchase that configuration now), you could assemble a powerful and inexpensive LC system with a third party hard drive and a decent VGA monitor.
BMUG Inc. -- 415/549-2684
James Engineering -- 415/525-7350
NEC -- 312/237-2264 (number to call for cable)
MacWEEK -- 02-Apr-91, Vol. 5, #13, pg. 6
MacWEEK -- 22-Jan-91, Vol. 5, #3, pg. 6
InfoWorld -- 11-Mar-91, Vol. 13, #10, pg. 38
InfoWorld -- 28-Jan-91, Vol. 13, #4, pg. 34