Nokia Messaging for Email is rolling out an update in a few weeks, The update is said to bring some bug fixes, in which the most significant fix is related to Destinations support on Symbian^1 devices (like the Nokia 5800 and N97).

Straight from Nokia Messaging Blog:

“Several issues were resolved around reliable WLAN connectivity. Please note that there are two steps to successfully enabling WLAN roaming: add your WLAN access points to the Internet Destination, and then also enable WiFi “sniffing” so that the device will notice when it comes into range of a configured WLAN. This “sniffing” setting is found under Settings / Connectivity / WLAN / Settings / Scan for networks. You can then select your Destination profile inside of the Nokia Messaging client.“

You can get this update when it’s available, through the Ovi Store and at their Service website, as well as through Software Update on your device.

Or you can get the installation file right now from the Nokia Messaging Blog.