Updated 11/16/2015: add IPv6 support and link user agent to StatCounter.

This snippet adds a link to geolocation and ISP data on IPaddress.com (IPv4) / ipinfo.io (IPv6) and the submitter’s user agent to the Entry metabox via the gform_entry_info hook.

<php
// Add IP and UA info to Entry metabox
add_action( 'gform_entry_info', 'djb_gform_entry_info', 10, 2 );
function djb_gform_entry_info( $form_id, $lead ) {
	// Don't show link if address is in IPv4 private or reserved range.
	if ( isset( $lead['ip'] ) && filter_var( $lead['ip'], FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE ) ) {
		if ( filter_var( $lead['ip'], FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 ) ) {
			$ip_info_url = 'http://' . $lead['ip'] . '.ipaddress.com';
		} else {
			// ipinfo.io has less detail, but supports IPv6.
			$ip_info_url = 'http://ipinfo.io/' . $lead['ip'];
		}
		echo '<a href="' . esc_url( $ip_info_url ) . '" target="_blank">IP info</a>';
	}
	if ( isset( $lead['ip'] ) && isset( $lead['user_agent'] ) ) {
		echo '<br><br>';
	}
	if ( isset( $lead['user_agent'] ) ) {
		printf(
			'%1$s: <a href="%2$s" target="_blank">%3$s</a>',
			esc_html_e( 'User Agent', 'gravityforms' ),
			esc_url( add_query_arg( 'useragent', urlencode( $lead['user_agent'] ) , 'http://gs.statcounter.com/detect' ) ),
			esc_html( $lead['user_agent'] )
		);
	}
}