Any with experience with running common Windows business programs such as Office apps, marine and land navigation software, on Windows running on VM Ware? Am considering doing it on my IBM T-23 1.0 GHz, 512MB, on a new 5400RPM 80GB 16MB cache HDD. Would it be too slow?

I think the performance will be acceptable, unless you are doing lot of fancy animation in your powerpoint slides.

Having run VMware quite a bitr over the last year I would say you should be fine, but you will have a hard time running much else at the same time. Consider getting a lite version of windows (or creating one) that will allow windows to run with less resources from the system. Remember with VMware your spliting the performance of your machine between two OS's.