Searched for this but seems no one has posted anything on it, so hopefully I'm not missing something obvious.

When you have a data plan and you are nearby a known wifi connection, it always seems to try connecting to the wifi no matter what. Sometimes the signal is so low that it can't hold on to it (certain parts of my house have poor wifi signal) but retries for maybe 3 times and then decides to fall back on the data connection.

So any way to sort out the connections by priority?

There is a way for setting each IAP a priority. See http://talk.maemo.org/showthread.php?p=1132203
The field to set in gconf is /system/osso/connectivity/IAP/<iap-id>/priority
where <iap-id> is the UUID of the IAP.

Note that If you set the priority of cellular connection higher than wlan one, then you would not get connected automatically to that wlan AP any more (as there would be higher priority IAP available).

thanks a lot
yes i realize that, i will do the switch manually when necessary

Why not set you home wifi connection to "manual"?