I know that most of us will skip over this one thinking that it can be done later. The truth be told: yes. In many cases it can be a good idea, especially if you did not check the water first and aren't 100% sure that you found a winner. You should spend some money on determining whether your product is worth pursuing (although, don't be too quick as it make take a little time to pick up...)
However, your logo is your mark and without it you'll lose quite a bit on your branding. It is important to understand that your logo will enter your visitors brain with more ease than anything else. If you do movies, then your introduction is your brand (remember Dreamworks with the kid and his fishing pole sitting on the moon?)
If you've been reading my Snap! Blog for a while, then you certainly have noticed the Snap! logo at the top-left. There are some recalls here and there as in the call to action box at the top-right and you probably noticed it just before the word snap...
In this very page, I also put the logo in the background. This version is a thin line with the same shape as the main logo. It's subtle and can be used in a background just like here. I don't generally do it with this logo because I think it makes it harder to read the content I write, but I guess you'll get the idea.
If you're no artist, I strongly suggest that you hire one. There are really only a very few cases where just the name of your company is enough (i.e. attorneys and accountants are a good example for such.) Most of us, however, are better off with a real neat logo. Make sure to get a very large one in case you one day want to print a large banner, a full page size version, a regular size version (around 100x100) and small versions as an icon (32x32 and 64x64 are generally standard) and a tiny one for your website favorite icon (this one is 16x16, except on the Macintosh where it can be up to 64x64.)
If you don't know anything about computer file formats, know that a better format is a vector based format. This is because a vector based format can be sized from very large to very small (generally down to 100x100) and still keep it high quality. There are two such formats PSD (Postscript Description or Photoshop) and SVG (vector graphics).
If the graphics person working with you does not offer such formats, at least make sure you get a PNG image. If your logo does not include a background, make sure that the PNG is transparent. You can test with old sorts of software, including Microsoft Word, by creating a page with a background color other than what you see as the background in the PNG: say the PNG is on a white background, create a Word document with a red background, and if it has proper transparency, you will see the Word document background instead of white.
Avoid JPEG unless your logo is a photograph (which I personally would avoid since a photograph is really hard to print on paper at all dimensions...) The huge problem of the JPEG format, that out weights the incredible compression, is that it destroys the image making it quite blurry.
Then display your logo in your website title and footer and call for action and your email marketing and everything else you can think of. If you do some off line marketing, then use it on your business cards, letter heads, envelops, advertising, everything and everywhere. This will help your potential customers to remember your brand.