Yes - as a visitor, you're typically limited to a six month visit (although you can apply for an extension while you're here). Since your from the Czech Republic - you will also need to apply for a visit visa if you want to come here as a tourist (i.e. you can't just come on your passport). Information is here:
http://www.cic.gc.ca/english/visit/apply-how.aspYou won't be covered by health care during this time (make sure you take insurance to cover emergencies). You also cannot work without changing your status to a work permit.
Changing your status to a work permit is going to be difficult in your case (in my opinion). In order to do so, you will first have to find an employer. That employer will then have to apply for something called an LMO - essentially, approval to hire a foreign worker. As part of this process, the employer will have to prove they were unable to find a Canadian for the role. (This will be quite difficult to prove right now given there are a large number of IT professionals in Canada, the economy has slowed down and more Canadians are looking for work). IF the LMO is approved, you can then apply for a work permit. If the work permit is approved, you can then start working. This entire process typically takes months. Since the process takes so long and there's a chance of refusal - many employers aren't even willing to consider foreign candidates. This is why I was wondering if you qualify for one of the working holiday visas (no LMO is required if you come under the working holiday program).
If you can't apply for the working holiday program for whatever reason - then I think you will face an uphill battle finding a job as a visitor here for the reasons I've stated above. If possible, I would suggest you start sending resumes and find a job/go through the LMO and work permit process before you come here - and be prepared to send dozens of resumes and hear nothing back. Again, your first challenge will be finding an employer who's even willing to consider you for a job.