First tar/gzip the blog and the database:

tar -cf old_blog.tar blog/
gzip old_blog.tar
mysqldump -h hostname.com -u username -p database_name > dump.sql
gzip dump.sql

Bring the blog and database to your local machine and set it up. For simplicity sake we will assume that the database name, username and password is the same as your live server.

scp user@hostname.com:/path/to/files/old_blog.tar.gz .
scp user@hostname.com:/path/to/files/dump.sql.gz .
tar -xzvf old_blogtar.gz
tar -xzvf dump.sql.gz
mysql -h localhost -u user -p database_name < dump.sql

Log in to your database and change the values of siteurl and home in the wp_options table to point to your local machine’s domain:

update wp_options set option_value = 'http://localhost:8888/domain.com' where option_name in ('siteurl','home);