help after ultrasnow!

[teequeue]

so i jailbroke my 3gs phone, got cydia up and running, then i have installed ultrasnow (as i wish to use an orange sim in a 02 locked phone)  as i installed ultrasnow it said reboot the phone, i did this and now i cannot whatever i do get the phone to turn ON!! the apple logo is coming up and just staying on screen i cannot now get into my phone....could anybody please help??? any suggestions are welcome, cheers