It is a good idea to get the landlord's permission to sublet an apartment, and, in fact, most leases in use in Laramie require it. Subletting your apartment does not release you from liability to the landlord for the acts of your subtenants. Therefore, you should choose your subtenant very carefully.
It is important that your subtenant be responsible to you for the exact same things for which you are responsible to your landlord. Therefore, make sure that your sublease requires the subtenant to be bound to the same obligations that you are to your landlord (i.e. late fees, etc.). By the same token, you should try to have the same remedies in the event of breach by your subtenants that your landlord has under your lease.
You can obtain sublease information from the Students' Attorney Program.