removing end of line mark with sed

[Begley Michael L]

Here's a simple one...
How do I remove the end of line marker from a stream?  for example,
if I have a stream that esentially looks like:
1
2
3
how do I make it into:
1   2   3

I tried      sed 's/\n//'      but that didn't work.  Thanks.

-mike begley
spam at hobbes.cc.iastate.edu
begley at forest.ecil.iastate.edu