I've been enjoying Phantasmagoria on my netbook (asus eee 1005ha - Win 7), however Dosbox stretches it to fit the widescreen. This hurts the image; if I run it in a window it looks much cleaner and crisper. Is there any way to run it with black bars on the sides so it plays in it's more natural format (is it 640x480 or 800x600)? I don't want to run it in a window.
Thanks!

Not really the right part of the forum to ask this, but see this thread for a general idea about widecreen "stretch" handling.
http://www.gog.com/en/forum/general/old_games_stretched_on_new_widescreen_monitors

What I do is change the graphical modes. Go to the .conf file (I think it's "dosboxPHANT.conf", and change the options in there to this:
[sdl]
fullscreen=true
fulldouble=true
fullresolution=1920x1080 (change to your res. 'x' needs to be there.)
output=openglnb
[render]
frameskip=0
aspect=true
scaler=none
Then it should have black bars and look nice fullscreen.

In the game directory, search for a .conf file. Edit it [with notepad for example]
In the [render] section change the setting on "acpect=", if it does slow things down, You may have to change the output mode in the [sdl] section, also available in the GOG's display setup for the game.
If that doesn't help, You may also try to edit the line "fullresolution=", and enter a fixed value in the desired aspect ratio, like 1600x1400, 1280x1024, 1024x768...
[edit]
Ah, too slow, again...
Damn You Silencer! Damn You!
[/edit]

I'd say it's exactly the right part to ask, since it effects DOSBox in general, not Phantasmagoria.

I meant that the question should be asked in Phantasmagoria subforum, because it was concerning Phantasmagoria, and not other titles. But it was asked in General Discussion, so I gave a more general answer :P.

Yes, but Orryyrro's point is that since the issue actually affects all DOSBox titles, the general forum is indeed the correct place to post it. In effect, Phantasmagoria is only used as an example of the problem.

Indeed, maybe they should sticky the solution or something, since some people want the games with the bars up the sides, and others probably prefer them distorted. (maybe?)

Do you really have that space in asp ect?
Just copy/paste the formatted text from here and it should work.

What he said should fix it. If it doesn't, you could always set "fullscreen=false", then just set "windowresolution=<whatever you want>". I have my DosBox set up to run that way on my home PC widscreen, and it works fine.
I had some trouble doing the opposite once; I actually WANTED to stretch the screen. I found playing with the "output" field finally solved it. Setting "output=ddraw" fixed my troubles with it (along with setting "fullresolution=0x0", go figure). I realized you want to do the reverse, so ymmv.
EDIT:
My DosBox config, in case you want to just run it in windowed mode (since I know this works for me):
[sd]
fullscreen=false
fulldouble=false
fullresolution=0x0
windowresolution=1440x1080
output=ddraw
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper.txt
usescancodes=true
[render]
frameskip=0
aspect=false
scaler=normal2x
Note that this set up will force the output to fit the screen in fullscreen mode, but in windowed mode it will stretch the video to whatever window size is defined in the config.
EDIT2:
If nothing else works, or just doesn't do what you want, try changing your "fullresolution=640x480" field to "fullresolution=original".

Fullscreen resolution is set to normal aspect resolution, which is probably native for the game. Change it to monitors native resolution or set either your monitor or gfx driver to do aspect scaling instead of stretch.

As I put in my EDIT2 above, I think that is what "fullscreen=original" will set DosBox to automatically do. If I am understanding the wiki correctly, this setting will have DosBox force the monitor into the closest resolution to the native output resolution that the monitor can handle:
"fullresolution = width x height | original
The resolution to use for fullscreen. If original is specified, DOSBox will try to switch the screen resolution to best match the resolution request by the application. For example, if a game in DOSBox is requesting a graphics screen resolution of (320 x 240) while your desktop is (1280 x 1024), DOSBox will perform the switch or try other resolutions that closely matches it, e.g. (400 x 300) if (320 x 240) is not available.
Default is original."
But, yeah, one can also force the resolution with this field. However, that will necessarily reduce the 'sharpness' the OP requested, unless the forced resolution is identical to the video output resolution, or the aspect ratio is an even multiple of the output resolution (such that one output pixel becomes 4, 9, 16, or etc actual pixels).

Thanks everyone for the suggestions. I ended up scouring the web a little bit and found this resolution to work:
[sdl]
fullscreen=true
fulldouble=true
fullresolution=0x0
windowresolution=original
output=ddraw
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper.txt
usescancodes=true
[render]
frameskip=0
aspect=true
scaler=none
The key part that was different from everyone else's solution was setting the resolution to 0x0. Hope this helps anyone else out there!