I have a column with most numbers repeated several times. In a second column I want to show each different number once only, eg:
A B
1234 1234
1234 369
1234 158
369 1125
369
369
369
158
158
1125
This is in Excel 2010 thanks.

This is exactly what the Advanced Filter was created for... here's a video tutorial using your data sample:

Using Advanced Filter - JerryBeaucaire's library (http://screencast.com/t/i85KNnlTFvf)