I bought a very beaultiful pink tv-monitor 26", model LG26LED6500 for my daughter and I also intend to enjoy it setting up in my slackware 13.37. Then I use a VGA cable and 6600GT nvidia card, but now I'm having a doubt because there aren't vertical and horizontal frequencies specs in this manual. Only:

Resolution- Freq. Horz / Freq. Vert
640x350 - 31.468 khz / 70.09 hz
640x480 31.469 khz / 59.94 hz
...
800x600 - 37.879khz / 60.31hz
1024x768 - 48.63khz / 60.00hz
...
1360x768 - 47.712khz /60.015hz
1280x1024 - 63.981khz / 60.02hz

I did a xorg.conf using a vesa driver and kde screen output was a 1024x768 - 61hz.

Section "Monitor"
Identifier "Monitor0"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
HorizSync 30.0 - 70.0
VertRefresh 50.0 - 160.0
Option "DPMS"

If I try to use a nvidia driver and xorg.conf piece above X break down. If I use any manual frequency parameters X break down too.

1)What's the difference between CRT config and tv-monitor xorg?
2)Have I use strings modeline monitor and modes screen in this situation?

Should be plug and play, use the D-SUB 15 (monitor cable). Let the graphics card determine the resolution on it's own from the EDID. No reason over complicate the configuration. Use an xorg.conf that only specifies the driver (nvidia). That TV has a native resolution of 1920x1080 according to LG. LCD/LED/IPS panels should be operated at their native resolution for best picture quality.

Thanks, my dear disturbed1!!!

I deleted xorg.conf > Input Device

Option "UseEdidFreqs" "FALSE"

There is a general note on page 19 (manual) about using 1360x768 resolution. If I try 1280x1024 and the established 63.981khz / 60.02hz provide only a 50hz kde screen. Can be a lcd dap or circuit lamp damaged when I have a incorrect frequency xorg settings?

I doubt it's the TV that's causing the problem. It is difficult to get the right resolution on TVs. Just keep trying different settings until it works reasonably well. In nvidia-settings make sure to use Overscan Compensation to prevent clipping the edges of the screen.