I'd recommend a PowerShot S95 - on Amazon.co.uk I see them for a little over Â£250.
The biggest factor in better low light images is sensor size - the larger the sensor, the higher the ISO can go without unacceptable noise. The second factor is aperture - the wider, the more light (and at P&S sensor sizes, there's no thin DoF issue with a faster lens, unless you are at macro distances).
The Samsung MV800 she's considering has a 1/2.3" sensor (I had to look at dpreview for that spec - Samsung's website lists the MP count, but not the size of the sensor - more evidence that the less you know, the more impressed you are by a 16 MP count...). The S95 has a 1/1.7" sensor - 50% larger than the MV800. The S95 also has a lens that's f/2 at the wide end, vs. f/3.3 for the Samsung - a 1.5-stop difference. So, you add the 1.5-stop faster lens to the slightly over 1-stop better ISO performance, and you are 2.5-stops better in low light. If she's willing to shoot in RAW, she can likely get another stop with the better NR you can achieve when processing a RAW image on a computer vs. the in-camera NR for a JPG.
Also, in really low light, the S95 does a 2x2 pixel binning for a 2.3 MP image (JPG only) that's actually not too bad.
The S100 is probably going to be a little better in low light (thanks to backlit CMOS and Digic 5), but that costs substantially more. I have and really like the S95, it's small enough for a pocket or purse. In fact, a few comments (hints might be a better term) from my wife about how much better my S95 is compared to her Olympus P&S was a stong factor resulting in me pre-ordering the S100. She'll get the S95 when the S100 arrives in a couple of weeks.