I'm thinking of removing my trailer's wheels and blocking up the trailer for the winter. Is there a problem doing this? If not, should I wrap something around the hubs to protect from snow, etc? What should I use? I don't want to use something that will cause the hubs to rust. Thanks.

It will be fine, just dont cover the hubs,etc with plastic or the cheap blue tarps. They trap air,resulting in condesation,which will rust. I have actually placed a 5 gallon bucket over them,and bungee cord to hold them on. Just make sure trailer is good and stabilized. 

It looks funny, but my tires and rims look new yet.

Probably not necessary to do all that. If you're worried about it I'd say to throw it up on some blocks but the rims and tires can stay on.  

I block up the trailer, and leave the tires on.

Thanks guys. This is a 4' X 8' utility trailer I converted for kayaks, using wood. Do you see any problem if I cover it with a tarp?

Not really.  It probably doesn't even need to be put on blocks, it's so light.

the most important thing is to keep the sun off the tires and wood.  That's what will do the most damage.  Put a tarp on and leave a chair or some kind of bump in the center of it to make sure water runs off and doesn't puddle.

damp rid never hurt under a tarp to suck up the moister just check it once a month and replace and dump as needed.

I just jack mine up enough to get the weight off of the bearings, leaving the wheels on. If for whatever reason it were to drop off the blocks, the tires are already on the ground, or slightly above it and no damage would occur.  This acutally happend on my old boat with the wheels off and I had a b!+ch of a time getting it back up. The only lucky thing was the hubs weren't damaged.

Thanks guys. I wound up blocking it up under the frame, with the tires a few inches off the ground. I'm waiting for wheel covers to arrive I ordered from Walmart.