The 2007 Impact Factors are now out (published on 17 June 2008). The ten Nature Publishing Group journals with the highest Impact Factors are as follows:
1 NAT REV MOL CELL BIO 31.921
2 NAT REV CANCER 29.190
3 NATURE 28.751
4 NAT REV IMMUNOL 28.300
5 NAT MEDICINE 26.382
6 NAT IMMUNOLOGY 26.218
7 NAT GENETICS 25.556
8 NAT REV NEUROSCI 24.520
9 NAT REV DRUG DISCOV 23.308
10 NAT BIOTECHNOLOGY 22.848
The Impact Factors of the Nature journals that publish original research are:
1 NATURE 28.751
2 NAT MEDICINE 26.382
3 NAT IMMUNOLOGY 26.218
4 NAT GENETICS 25.556
5 NAT BIOTECHNOLOGY 22.848
6 NAT MATERIALS 19.782
7 NAT CELL BIOLOGY 17.623
8 NAT NEUROSCIENCE 15.664
9 NAT METHODS 15.478
10 NAT NANOTECHNOLOGY 14.917
11 NAT PHYSICS 14.677
12 NAT CHEM BIOLOGY 13.683
13 NAT STRUCT MOL BIOLOGY 11.085
(Nature Photonics and Nature Geoscience are not old enough to have been awarded an Impact Factor this year.)
Readers can create their own lists of journals by subject area, title, Impact Factor or publisher, at ISI Web of Knowledge.
There is a free-access account at the ThomsonISI website which explains how the Impact Factor for journals is calculated.
Discussion of the 2007 Impact Factors, and of citation in science in general, is taking place at the Nature Network Citation in Science group, which you are warmly invited to join.