Looks like it may well go through. Zenit have lowered their price-tag for Arshavin:

Spurs' Berbatov At Man United For Medical After Zenit Lower Arshavin’s Price?

"Other reports are suggesting that an agreement has been reached between Zenit St Petersburg and Spurs to allow Arshavin to leave the Russian side, and it is believed that this agreement is paramount to letting Berbatov join the Premier League Champions."