William Lam has posted a detailed explanation of how to quickly and easily configure multiple ESXi hosts to forward logs to multiple syslog servers:

…with ESXi 5.0 you can now forward to multiple syslog servers which is great for providing redundancy when shipping your logs. In addition to supporting multiple syslog servers, with the release of ESXi 5.0, you can specify different transport protocols: UDP (default), TCP and SSL.