MyStyleWindow.com, an online store where fashion retailers can promote their products and link to their e-commerce sites, is to launch on 1 March, a week ahead of Stylefinder.com.
The Conde Nast site will feature a search facility to find an item by type, colour or price.
Other features include "Trends - Stylefinder", which will predict the trends each season; "Martha's Buys", where stylist Martha Ward will provide fortnightly selections; "Celebrity Style", which will give advice to consumers who want to copy celebrity looks; and "Street Style" to inspire users with photos of stylish shoppers.
Conde Nast claimed it will have more than 5,000 items to buy, compared with the flagship TopShop store, which usually stocks about 1,200 items.
The target audience for Stylefinder.com is women aged 15 to 45, who are frequent fashion and beauty shoppers.
Clare Alstin is in charge of editorial and Serena Privett is the commercial director for both the site and for the rest of Conde Nast Interactive.
Meanwhile, MyStyleWindow.com will include a fashion-focused social network and updated content detailing where to buy the latest celebrity fashions online.
It has already signed up a number of advertisers including Next, Marks & Spencer, Debenhams and Harrods.
The website has been founded by internet entrepreneur Cas Ojo.
Her business partner, and director of the company, is Paul Giles, who runs website development firm E-Business Engineers.
Ojo said: "When the likes of Nike and Tommy Hilfiger sign up, which they did last week, it gives our proposition immediate pull."
Ad sales for the site are currently handled in-house.
Earlier this month, Media Week revealed that Sky Media has been appointed to represent online fashion retailer, Asos.com, an acronym for As Seen on Screen, which helps people recreate the looks they see on celebrities.