Nikon D50 and Sigma 18-50 & 55-200 lens kit

I bought my Nikon D50 camera about a year ago, and have finally got
sick and tired of the 28-80mm lens it came with. I found some great
deals on a Sigma 18-50mm and 55-200mm lens kit (comes with lenses,
carry bag and microfiber cloth) for 200 bucks. I saw also a Sigma
18-125mm lens, but people were complaining about the lack of clarity
with that lens.

Has anyone used a D50 with the 18-50 & 55-200mm lens kit, or the
18-125mm lens? I already bought the 18-50 &55-200m lens kit, and it's
on it's way via UPS, and I should have asked around first, but I'd like
to know if anyone has taken some pics with their D50 using these lenses
and if they are any good. the problem I am having is that I can't spend
more than 250 on a lens, and I want the wide-angle 18mm but I also want
zoom capabilities. If anyone could suggest a lens (or lenses) that fit
that criteria, could you kindly reply and let me know? I would greatly
appreciate it.

Also a quick side question. Why when I take shots indoor with my D50
and use long exposure settings does the color of the picture turn out
yellowish? I have the ISO setting as 200 so I won't have graininess,
but the yellowing is pretty annoying. Of course I can use the flash,
but when I can't use flash, the colors come out yellowed. Thanks again
or any help that you guys could give.

The Nikon 18-80 is superior to the two Sigma lenses and you ahould hold on
to it for use in those focal ranges.
Lenses in the 55-200 range from all manufacturers, including the Nikon, are
generally disappointing in my experience. If you want a 55-200 then simply
add one of these. The Nikon 55-200 is around $250 although I am not sure it
is really any better than the Sigma in any way.
The Sigma 18-200 is a good performer in the 55-200 range. The 18-200 class
is a convenient way to get reasonable quality telephoto performance in a
reasonably sized lens that is convenient for general use and travel. Sigma
will have an image stabilized version of this lens in the next few months.
The Nikon 18-200 has image stabilization and is excellent but expensive. The
Sigma and Tamron 18-200 can be had for around $300 if you shop around.
However the Nikon 18-80 that you have is a better performer at the wide end
of the zoom, but if you do not know why that is so it is a non-issue for you
(as it is for most users).
The 28-200 class for 35mm film are generally not very good for use with film
cameras. However since the dSLR is centered in the "sweet spot" of these
lenses their apparent performance is significantly better with dSLRS,
especially at the medium to long end of the zoom. These lenses can be had at
bargain basement prices even new. Many people have these lying around having
abandoned them for use with film cameras--if you have one of these you may
be surprised at its apparent performance with a dSLR.
Lenses in the 80-200 category, while large, will generally be better optical
performers if ultimate quality is what you are after and there may be used
bargains available. However for practical uses, particularly if one is
comfortable with post camera image processing, it is hardly worth it to lug
around these large lenses for amateur/snapshot purposes.