The "Skype on Three" app works ok on 3G but it was specific to the 3 network as it routed the free Skype calls / IMs over GSM - actually prompts you to turn off Wi-Fi. Remember that it also worked on the "Skypephone" which didn't even have Wi-Fi.
3G (even GPRS probably) is "fast" enough (bandwidth-wise) for VoIP and Skype though video quality may be variable and depends on the device too. Jitter and high latency (rather than bandwidth) are the determining factor for VoIP (like gaming).
Remember also that other operators may
still be blocking the Skype protocol and/or VoIP ports on 3G, depending on what tariff you are on and whether you are using some operator-specific client app/service.
If you can make a VPN connection to something and Skype them works that may tell you if it is a network issue. PPTP is old and less secure but as (a) by default tends send all traffic through the tunnel and (b) the client is present on most devices, it's good enough for a quick test anyway.
prompt $P - Invalid drive specification - Abort, Retry, Fail? $G
prlzx on n e w n e t: ADSL2+ / 21CN at 3.5Mbps / 800kbps
Edited by prlzx (Wed 06-Feb-13 14:07:55)