I am curious to know which companies are entering the stock exchanges.
Is there any list at the exchanges which companies are new listed or are announced to join the stock market in the near future?
Market Watch has an IPO calender with details of upcoming IPOs that should provide most of the information you need.
For months prior to going public a company has to file financial documents with the SEC. These are available to the public at www.sec.gov on their Edgar database. For instance, Eagleline is listed as potentially IPOing next week. You can find out all the details of any IPO including correspondence between the company and the SEC on Edgar. Here's the link for Eagleline (disclaimer, I have not investigated this company. It is an example only)
https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001675776&owner=exclude&count=40
The most important, complex, and thorough document is the initial registration statement, usually an S-1, and subsequent amendments that occur as a result of new information or SEC questions. You can often get insight into a new public company by looking at the changes that have occurred in amendments since their initial filings.
I highly advise people starting out to first look at the filings of companies they work for or know the industry intimately. This will help you to better understand the filings from companies you may not be so familiar with.
A word of caution. Markets and company filings are followed by very large numbers of smart people experienced in each business area so don't assume there is fast and easy money to be made. Still, you will be a bit ahead if you learn to read and understand the filings public companies are required to make.
Thanks to the other answers, I now know what to google for.
Frankfurt Stock Exchange: http://en.boerse-frankfurt.de/equities/newissues
London Stock Exchange: http://www.londonstockexchange.com/statistics/new-issues-further-issues/new-issues-further-issues.htm