By Shawn Ward, Geezeo co-founder

Movie rental giant Blockbuster, Inc. ( BBI) is losing ground to a growing number of digital competitors.

To combat Internet-based rival Netflix, Inc. ( NFLX), Blockbuster spent 2007 fine tuning its total access plan, which allows customers to order movies online with the convenience of returning them to Blockbuster stores.

The results this year have been underwhelming.

Blockbuster's share of consumer spending on rental movies dropped to less than 43% in September from 52% in January, according to the new Main Street Spending Index compiled by Geezeo, a personal finance Web site that helps consumers track their spending.

Click here for larger image.
Source: Geezeo.

In addition to losing market share to Netflix, advances in digital media are creating even more competition for Blockbuster.

Cable companies such as Time Warner ( TWC) are selling on-demand movies, TiVo Inc. ( TIVO) is offering movies through a partnership with Amazon's ( AMZN) Unbox service and free websites, like Hulu.com, are also serving up movies for online viewing.

Not surprisingly, both Blockbuster and Netflix are experiencing a drop in total spending per customer. The average amount Geezeo users spend at Blockbuster each month declined 13% since May to $23.44 and fell to a monthly average of $16.53 at Netflix in the same period, according to the Main Street Spending Index.

Geezeo's Main Street Spending Index tracks more than 4 million consumer transactions from 800 companies doing business in the United States and Canada. Market segments include retail, dining out, entertainment, household and utilities. Data is anonymously collected weekly and based on up-to-date bank information.

To view the full index and see how other stocks are performing, click here: Main Street Spending Index.

For more information about Geezeo or to track your own expenses and find ways to save, visit www.geezeo.com. More than half of people using Geezeo's free budget tools are saving an estimated $1,200 annually.