I have noticed a few links between theses numbers and things on the island and things before they were on the island. You might know most of these already but if you dont i hope this helps you.
The numbers: 4 8 15 16 23 42
Links:
1.48 survivors
2.Oceanic flight #815
3.There were 42 rows on the plane
4.Ana Lucia was on seat 42F on the plane
5.Claire was 8 months pregnant when she arrived on the island
6.The plane gate was 23
7.The number were on the hatch
8.The numbers brought Rousseau and her team to the island, which brought death to her team, then Rousseau sent out the numbers and they were heard by two men, one is in a metal hospital and thats were Hurley heard them, he used them in the lottery, won and then he brought bad luck to people around him, then he went to Austrailia to find out about the numbers and then he got on the plane. These numbers bring people to the island. So maybe these numbers are connected to the other charecters too.
9.You find out in the second series that these numbers have to be typed into this machine or something every 108 minutes or the world will end. The man who does this is Desmond, the guy that Jack met, and he is in the hatch.
I hope this was to some use to you and if you find out anymore links can you please say here because im really interested in them.
I also found what might be another link (not connected to the numbers) - the plane journey was meant to be a total of 14 hours and there are 14 main characters. This might not be an actual link but you never know.