From Gallery Codex
Migrating from 1and1 (or any other host) to Dreamhost.
NOTE: Use the WPG2 Promo Code to get $50 discount off your First Hosting Bill!
A very quick summary to follow (I would personally recommend using the one click installation for both Wordpress and Gallery2 that way you can upgrade painlessly.
- Clear your G2 Template, Database, Session Cache
- Deactivate all your WP Plugins
- Turn off Wordpress Permalinks
- Turn off the Gallery2 Rewrite Plugin
- Dump your 1and1 Wordpress + Gallery2 DB and Zip them up into a directory in your 1and1 account.
- Zip up your g2data, Grab a Copy G2 Theme (if you have a custom one), Wordpress Theme (if you have a custom one) and any plugins.
- Log into DH Panel and create a DB for your WP+G2 (Separate or the same)
- SSH Into your Account and use WGET (or ftp) to grab your 1and1 DB+Other Files
- Restore your DB
- One Click Install WP + G2 using the DB's you have already defined in Steps 4
- Restore any plugins, G2 (WP) Themes, activate them (remember to revalidate the WPG2 plugin!)
Some links with a heap of information