Can anyone help me in using my tesco internet phone with another programme?

i have read the various posts stating it can be done, i have installed skype and and i get the test call coming thru the handset but i cant make no calls as it says i need to put skype credit on my phone, i have £5 of tesco credit on it.
can anyone give me some advice please?

There's your problem - you have £5 of credit on the Tesco service - not Sk(h)ype.

i understand that bit, but can i still use the number the tesco service gave me? and can i call other people who have these phones?

Yes, but you have to use the Tesco software to do so.