There are several possibilities for ice climbing around Prague.
One can be suitable for really beginning near a village Vrane nad Vltavou (0,5 km before Vrane nad Vltavou on the way from Zbraslav on right side of river Vltava. It was several meters vertical but mostly about 50 degrees laying icefall of height about 30 meters. Look at photos from the last winter (2003):
The Ice near the town of Vrané nad Vltavou.Belaying by screws, nearly vertical part.The step up is realy on the road - the ice at the road and view to Vrané.Abseiling and overview to a wall with icefall.
Map is here.
The second area suitable for ice climbing not far from Prague is Marenka a 70 meters high cliff above Vltava river near the Slapy dam. It was last year (February 2003) more mix climbing then clear ice but I remember 16 years ago very large icefall. According this year news it was out of ice but the weather is geting ice-up more hopefully.
The cliff is on the right side of the river.
The access is possible for village of Krnany or village of Teletin not far from Stechovice. There you have to reach a small weekend house village Proudy and there is the cliff accessible across a private garden.
Look at photos:
Partly iced route Komín (Chimney) at MařenkaDown part of the Mařenka iceMařenka - the middle of the route Komín (Chimney)
Map is here.