At at a time when valuations are coming crashing down for Internet companies, Twitter may very well end up doubling its valuation.

Twitter is looking to raise some serious cash, according to a report by TechCrunch over the weekend. Apparently, $250 million is the company's valuation and they already have IVP signed up on the term sheet.This is well above the nearly $100 million valuation the micro-blogging site had last year. 

From the report, "Rumor is Twitter hit up more than a few venture firms to pitch the $250 million valuation, and got more than one no.”

Back in November of 2008, Facebook attemped to acquire Twitter for $500 million, but Twitter rejected the offer, due to the proposition consisting mainly of stock as opposed to actual cash.  Facebook and Twitter share a key similar feature, micro-blogging.  While some bloggers are using Facebook's "Status Update" feature, others are tweeting away on Twitter's "What are you doing?" updates.  Facebook is currently valued at $4 billion.  Microsoft had valued Facebook at $15 billion back in 2007.

Twitter, with 4.5 million unique visitors per month, is obviously making sure to snag some investments for surviving the economic downturn and comfortably fleshing out its yet to be business model.