1. To get your free account, REGISTER HERE.
[Edublogs.org users: no need to register separately, just add widget - see here.]
2. You will be sent a password by email with login instructions.
3. Copy/paste a few lines of HTML from your ClustrMaps login page onto your own site.
Briefly: Stick to your 2,500-visitors-per-day limit (monitored with some leniency); make sure the thumbnail map is actually visible.
Less briefly:To maintain ClustrMaps as a free service, we politely request that users follow a very small number of 'good user etiquette' rules, which allow us to provide a good service to all users. These are specified more fully in the terms and conditions, but the key highlights are as shown below:
Breaking of the rules, even in our lenient interpretation, will lower your 'karma' score, which can progressively lead to: a polite advisory email notification; appearance of a 'polite notification image' in place of the actual thumbnail map; suspension of the ClustrMap thumbnail and counter, or (eventually, and after a suitable warning) complete ban of access. We don't really want to 'police' the service, but on the other hand 'bad etiquette' can really mess up the service for a lot of users, so we try to keep an eye on things to help promote the well-being of all users.