There isn't any real limitation to the functionality of MSSQL with log shipping - at least not the "roll your own" kind i've used in the past. In my experience with log shipping (SQL2K), the destination database can be accessed by users in between the times when logs are restored to it. At that point, user connections have to be killed as the database needs to be in single user mode.

My understanding of licensing is that if the destination server is used only for failover, a second license isn't required. However, if you allow users to connect to it, i would think a second license would be necessary.