Hi Favo,
Some things to be aware of if you do a newsletter:
If you start by sending it out from your own email client, check with your ISP first - some of them will look askance at an email going to 20-100 people at once.
Better is a mailing list script on your website.
A number of big sites - like Yahoo etc - were thinking last year about blocking any incoming email sent bcc. So your subscribers from those sites' email accounts might never get your newsletter.
If you'll have anything which needs to line up - eg table of figures - make sure to use a monospace font like Courier New. The usual fonts will skew tables or columns.
Make sure to include a way for readers to subscribe and unsubscribe in each issue.
In your sign-up area, make very clear that you won't abuse [sell etc] subscribers' email addresses.
If you want max compatibility with old email clients, use a line width of around 60-65 characters - some old apps wrap at that. Also looks better IMO.
Use spaces rather than tabs for indents.
For the first few issues, send it to yourself only before to the list. There'll usually be something you forgot, until you get used to it
Plan carefully what your "From" address and Subject Line will be. These are your only means for getting your email actually opened - don't delude yourself that your subscribers will be eagerly waiting for your next issue
I used the well-known HTML and programming editor
EditPlus for all my newsletters. It has great features to simplify the job.