I downloaded the 2.3 version in .tar.gz and ran tar as usual, but I get an error:
email@example.com [~/public_html]# wget http://wordpress.org/latest.tar.gz
Resolving wordpress.org... 126.96.36.199, 188.8.131.52
Connecting to wordpress.org|184.108.40.206|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/octet-stream]
[ <=> ] 3,502,080 2.92M/s
07:50:43 (2.91 MB/s) - `latest.tar.gz' saved 
firstname.lastname@example.org [~/public_html]# tar -zxvf latest.tar.gz
gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error exit delayed from previous errors
Why is it? This is a BlueHost PHP5 & HighCPU server.