I occasionally use multiple accounts from the same physical desk, but not on the same computer. You can in most cases buy a PC which has all of the requirements for UO, without the monitor and whatnot, for under 75 dollars. That computer, used in conjunction with your current PC, and a KVM switch (4 channel basic KVM = about 25 dollars), is the best legal method I have personally found.

I can change between accounts (as infrequently as I actually use it) in a single second using a hotkey on my keyboard. Each account runs on a PC independantly, does not interfere with the another, and does not share resources.

Not a bad deal for under 100 beans, and you can use the secondary PC to host a web site, or for storage, etc. when not in use. Personally, I run all my email and other programs or utilities which have similar resource requirements to UO on an alternate computer.

ADDITIONALLY:
There are various illegal programs which allow you to open a second client, and connect to UO (which I of course won't get into). The one I remember from the past which I think is referred to in a post above is "Nightmare Multiplicity".

UPDATE:
I have had numerous static IP addresses available to me for a while, and did not consider that many users do not. The information above assumes that an internet connection is available on both machines, via a router or alternate networking method. You can in fact "share internet connection" with the secondary machine from within Windows ME/2000/XP/Vista (service pack and update variations acceptable), on a "single line" and still obtain the desired effect.

Just to give you an idea, I use the XP fast user switching when I need to transfer something between accounts. I have an AMD 64 3500+ with a gig of ram, and the actual switching between accounts is slightly laggy (the hard drive hits alot - could probably reduce this with some more ram), UO runs fine under both accounts. It's just the actual switch that takes a few seconds. Otherwise, no lag.

Merc, !!! kind of processor and how much ram do u have on ur laptop?

I travel for work and when i am on the road i would still like to play uo since most hotels have internet nowadays.

I personally don't think that a laptop that is even remotely current would have any problems running uo. I have one that is 2 years old now and I play EQ on it quite a bit.