The bidding for Yahoo!'s (YHOO) assets just got more interesting. According to Bloomberg, AT&T (T) - Get Report has made a bid for Yahoo's core internet assets, meaning that the telecom company is now competing with rival Verizon (VZ) - Get Report . Just last month sources had indicated that AT&T wasn't interested in bidding. But now, if AT&T has joined the bidding, it represents a challenge to Verizon, which had been considered the frontrunner. The Wall Street Journal reported recently that bids are expected to come in significantly below the $8 billion some analysts were projecting.