Hello & Welcome to the SSWT Forum
When you say "online store", I assume you plan to build a website around the products you would like to resell? To find wholesale distributors, you might try doing a search at Google, such as:
http://www.google.com/search?sourceid=n ... Bwholesale (or get more specific with the search, such as: 'dell+wholesale' or 'monitor+wholesale' etc)
You might also consider Affiliate Programs - many of these will give you the HTML code to place on your own web pages to display the products and track your sales. Here are a couple to consider:
http://simplythebest.net/affiliates/aff ... uters.html
http://www.gateway.com/programs/affilia ... asp?seg=hm
I know that Dell has an Affiliate Program too. You can always do a combination of wholesale + Affiliate Programs. The perk to being an affiliate is that there is no upfront expense, no inventory to stock or shipping to worry with - you simply make commission on the sales you refer to that company. You could work with several merchants, offering a variety of items such as software, hardware, access to tech support lines, driver downloads, etc.
Keep us posted as to what you decide - and of course if you have any questions!