It's not free, but Opensystems makes a product called PrivateI, which runs as a service. It gives you much more than just a simple syslog (alerting, reporting, remote web access, filtering, enhanced queries, etc.)........ I would avoid this product however if you plan to deploy it in a large-scale network, as it does not scale all that well, and the last few releases are buggy. Unfortunately, this is not a market with lots of competition, so you this is probably the best you're going to get if you willing to pay.
