Exchange 2010 maintains a protocol log for RPC Client Access service. Logging is enabled by default. The log files can be found in %ExchangeInstallDir%LoggingRPC Client Access. The log files have connection information for the various clients. It is of not much interest unless you have issues with clients connecting to the mailbox.
The settings for logging can be changed by editing the Microsoft.Exchange.RPCClientAccess.Service.Exe.Config file in the Bin directory.
You can enable/disable logging, change the max size of a log file (10mb by default), change the retention age for log files (30 days by default), max storage for the log files (1GB by default), logging directory etc by editing the appropriate values.