[H4]

Check these out. Might be worth running something like these in the winter if you get lots of snow and switching to different tires for the rest of the year.
<a href="http://www.atvtiresale.com/maxxis-snow-" target="_blank">http://www.atvtiresale.com/maxxis-snow- ... -p-66.html</a>

Don't know if suitable sizes are available or if anything similar is offered by other manufacturers. It would be interesting to see how they work especially as they grow in diameter as they spin.

 

[H4]

Here is a pic of the tires that were on my bike when I got it. 24x9x11 front & 24x10x11 rear. They were well worn and just about useless in the bog but I could usually run circles around the bikes in our group in the snow. They stayed on top when the more agressive tires dug in. As long as I was out front and didn't try to follow in the ruts dug by the other bikes I rarely got stuck. If the snow is deep your best bet is to get the widest tire with the least agressive chevron pattern tread to stay on top.

 

[H4]

Had those on the rear. Gheng Shin's I think. Forget the actual brand on the front. They were great on the trails but only 2 ply and as a result were full of plugs, including 5 in one hole in a sidewall from a railway spike from the old rail bed.
They were better in the snow than my new Super Lights but who wants to ride around on worn out little 24's when you can tear stuff up and get even more stuck with some real tires!