Eigg is owned and cared for by the Isle of Eigg Heritage Trust  which was set up in 1997 by residents of Eigg and various other organisations.
There are two scheduled boat services that connect Eigg with the mainland:
If not travelling to Mallaig or Arisaig by car, you can reach the ferries by scheduled ScotRail train service via the West Highland Railway (although note that the pier at Arisaig is not as close to the railway as the pier at Mallaig).
The famous ScotRail  'Deerstalker' Caledonian Sleeper provides first class (single cabin) and standard class (double cabin) sleeper and reclining seat travel between Fort William and London Euston every night except Saturday. Local trains connect to Mallaig.
If travelling by day train, travelling to Eigg from anywhere further south than Fort William is only possible without an overnight stop in Mallaig on summer Saturdays, when the early morning train from Glasgow Queen Street station connects with the second CalMac sailing to Eigg.
Travelling from Eigg to points beyond Fort William by day train is likewise only possible on summer Saturdays and Sundays, when the first CalMac sailing from Eigg connects with the train to Fort William and Glasgow Queen Street on Saturday and the Arisaig Marine ferry allows passengers adequate time to reach the station at Arisaig in order to catch the train to Fort William and Glasgow Queen Street on Sunday.
It's a small island, so it's easy to walk from end to the other.
Bicycle hire is available.
A craft shop near the pier at Galmisdale sells locally produced goods as well as a range of books and souvenirs.
Eat & drink
There's a tearoom near the pier at Galmisdale.
There are a number of guest houses, self catering cottages and bothys, plus a basic campsite by the bay near Galmisdale.